Joker was introduced in 1940 in the very first issue of Batman comic, but contradictory to the popular myth, his origins were never meant to be ambiguous or left for interpretation. Batman's earliest stories were based on Pulp stories with similar main characters, such as The Shadow. Pulps are short, one issue murder mystery stories. They are not character driven, nor do they have any continuing storylines and continuous plots. They're simple detective stories with the mystery, detective and perpetrator. Again, such stories are not based on characters and dont focus on them, their personal stories, backstories or character development. Even when Batman got his origins, they weren't even included within any actual stories. They were just presented in two separate pages which were an extra in the issue.
'It may be significant that so many villains first arrived on the scene the way Joker had, without origin stories. They were granted the courtesy of being accepted as what they had chosen to become' (Batman: The Complete History).
In short, no villain had origins at first, nor there was even any kind of hint of any intended ambiguity. About 2 years into the series, it started changing more and more into the adventure series and shed more light on characters, their intentions, motives, stories and character traits and developing relationships. Once that was established and the Batman series fully changed into a conventional adventure series, characters were being more crafted and backstories were given to them.They started to appear in late 40's and Joker's turn came in 1951's Detective Comics #168, written by the co-creator of the character Bill Finger and with artwork credited to Bob Kane, also a co-founder.
In this issue, Batman and Robin are asked to be guest instructors at the University's criminology course. After lying out some background for good detective work and getting to know the students, he gives assigns them a 10 year old case even he couldn't figure out. An identity of a masked villain called Red Hood who disappeared without any trace
When Batman finally encounters the Red Hood during a robbery, the villain appears to be quite cocky and makes it clear that thanks to his disguise his identity will remain a complete mystery.
Red Hood makes an escape and the reports about new robberies committed by him reach Batman. A month later, Red Hood gets cornered by Batman and escapes seemingly sacrificing his life. He was presumed dead but the body was never recovered
One of the boys named Paul helped them solve the mystery and revealed that the Red Hood was a lab worker trying to steal $1 Million in a card factory to retire forever. After his dive into chemicals, he became disfigured and his skin and hair were permanently dyed - introducing The Joker! It's important to note that it was his physical appearance that pushed him into madness and made him decide upon his new image/identity
While his craziness, name and colors were explained, the frozen grin on his face wasn't addressed. To read more about Joker's frozen face and the origins behind the idea read The Complete Joker History article. Hi real name and pre-Joker identity remained unknown for the readers, aside from the fact that he was a lab worker
The origins were now set for Joker like for other villains and remained untouched for decades. In 1980's The Untold Legends of Batman, they were once again revisited by the 80's audience. In this issue, written by Len Wein and illustrated by Jim Aparo, the story remained consistent and unchanged
From mid to late 80's DC released an Official character guide called " Who's Who in DC Universe" which collected all the info and character traits in a encyclopedia-like style for every major character in DC. Joker's entry recalled the old known canonical origins
In 1988 Alan Moore decided to retell the origins but at the same time expand in the areas that weren't touched upon previously. Moore was sure not to contradict the established canon since he himself doesn't like inconsistencies in established canon
And the Joker's origin? Had he had one before that?
Alan Moore: He'd got a kind of muddy kind of origin. They'd said that he'd been the leader of a criminal gang called the Red Hood Mob and that while trying to escape from Batman he'd swum across this river of chemicals. And that was about it?
AM: That was about it and this was from a story from, like, the late '50s or something and so I thought "Okay, I won't contradict that," because I kind of believe in working by the rules of the material as it already exists but I can put a lot of spin on that. (Barry Kavanagh int., 2000)
While trying to stay true to the established origins as possible, he build the character behind the mask from scratch and infused it him with deep story and pathos, as he usually did with his characters, yet still preserving the fact that the young man worked at some point in the lab/factory. The pre-fall Joker was now a struggling young comedian who had trouble making ends meet and supporting his pregnant wife.
The reality of life has gotten hold of him, and he decided to cross the line and help with a robbery. The two gangsters that hired him made him assume the identity of a known robber Red Hood, which is just an identity assigned to different people, not a single gang leader as Police and Batman thought. While still not sure about this move, he wants to do it just for his pregnant wife, yet finds out she dies in an accident the night of the robbery, but there's no turning back with the gangsters.
From Batman's POV, Red Hood got caught by surprise,"his" thugs get killed and the panicked Hood makes a shocking move by jumping into the river where toxic wastes are emptied.
There's a misconception that the story Moore presents in The Killing Joke is not a real story of Joker but merely a figment of Joker's imagination. There's no indication that the flashback story that is intercut with the current story isn't true. The only line that can be taken as an argument is Joker saying that he prefers to have a multiple choice when it comes to his backstories, yet he also says that he does not remember his past so there's no assumption that the flashback story is him remembering.
It's rather a separate story , poetically and appropriately intercut within the contemporary story of Joker kidnapping Gordon's daughter. Then there's the fact that for decades Joker's origins were set in stone and were not contradicted by Moore, who even said himself that he doesn't like inconsistencies with previously established canon. And then you have Moore talking about infusing the character with pathos and dramatic story. It wouldn't not be so if the flashback was merely a made up figment of Joker's imagination, because the pathos given to the character would just go out the window as part of that imagination.
You made the villain such a pitiful figure. In the comics for years, he was a psychotic maniac who kills indiscriminately, just does terrible, terrible things, and you made him so pitiful and sad.
Alan Moore: I suppose that's what I was saying. Well, psychotic murders -- the key word there is "psychotic," which is, as far as I know, an illness. This is not to say that people shouldn't be entitled to feel rage or the lust for revenge when something happens to them at the hands of somebody like this, but you've got to remember at the end of the day it's not strictly speaking that person's fault. That something has happened to them, they have made some bad decision in their life, and while all of us are responsible for our actions, sometimes people get broken and it is increasingly difficult for them to know their own actions. So I suppose that if there was anything actually being said in "The Killing Joke," it was that everybody has probably got a reason for being where they are, even the most monstrous of us. (salon.com, 2009)
On top of all that, Moore has never ever hinted or undermined the legitimacy of the flashback story. And most importantly, the flashback story has been confirmed in past issues multiple times, which is going to be addressed in the article later.
The one who actually originated the retrofitting idea that the flashback story isn't true (at the same time acknowledging it was meant to be and disliking the fact) was the artist Brian Bolland.
It's important to note that he was not the storywriter and that he stated so only at the time of the release of The Dark Knight when DC was heavily pushing the angle that the movie was taking, which was to have Joker's origins ambiguous or purposefully unknown, which was an idea which originated solely from the sentence Joker said in The Killing Joke. It's also worth noting that Bolland statement was in The Killing Joke's rerelease in 2008, the same rerelease which changed the colors of Joker's outfit to match Heath Ledger's suit and added black around Joker's eyes and removed the yellow from Batman's emblem. Point being, the rerelease was clearly altered so it would match the movie, and so was Bolland's idea of discarding the origins which are actually shown to preserve the multiple choice angle the movie took.
One should also have in mind that aside form the idea being appealing to David Goyer and the Nolan Brothers, it would nullify the long established Joker origins involving permanent white skin which Nolan did not want to use in order to fit the character into our real world. By undermining the credibility of the origins, it erases them as canon in public's eyes and leaves a blank card for the filmmakers
The 1989 Batman deviated from the story a bit. Michael Uslan, producer: After much discussion, it was agreed that for the movie the Red Hood storyline would be too confusing, time-consuming, and unnecessary to include in the film. There was no compelling reason to add a third identity to The Joker. And so, it was Jack Napier who took the plunge into the vat of chemicals, not the Red Hood.(BITF 2002)
Joker still is born out of a criminal falling into vat of chemicals that emptied into the river, but the pre-Joker character was different.
He wasn't a robber but a mob hitman instead who already had psychological issues and was a multiple murderer who was doing hits for the mob for many years. According to the filmmakers in Shadows of the Bat documentary, they decided that it wasn't believable that a person can be so evil just by falling into chemicals. The fall has to have been the triggering mechanism to release or amplify an inner madness.
As in the comics, it was the first sight of his altered look that does the trick, and as in The Killing Joke, he just breaks laughing once he sees himself
The name Jack Napier was adapted into comics and written stories beginning with Dennis O'Neil's story "Images"
The first time Moore's story was referenced was in 1990's Batman #450. In this issue, after getting seriously injured Joker actually regains his sanity and recalls his entire life alone in the room while struggling with his confusion about what to do next and which road to take
In the following issue, Batman #451, it was Batman who was recalling the story presented by Moore. The Killing Joke's flashback story was now confirmed to be a part of canon continuity and the real event that really happened
The next reference/recollection to Moore's story was in 1993's Legends of the Dark Knight #50, written by Dennis O'Neil. In this issue it was Batman in disguise who recognized Joker by his voice and recalled what happened with Red Hood who jumped into the toxic river in panic
In 2004's Batman: Gotham Knights #54 Moore's story was not only recalled but also expanded and continued. A witness comes forward who knows that the comedian's (named Jack Napier in comic books since 1993) wife was actually killed to look like it was accident by the same mob that was trying to get him to participate in the factory robbery.
Ironically, while some of other villains' origins were changed throughout the years like Catwoman's, Joker was the one whose origins remained so consistent for so many decades. It was until 2008, the release year of The Dark Knight and the year where DC started pushing the multiple choice theme and undermine the credibility of Moore's story, that Joker's origins were remade. It was in Batman: Confidential #9 where we get to meet a bored criminal named Jack who wants to face Batman one day. When he actually does, Batman throws Batarang to stop him from escaping and cuts his face leaving a Glasgow smile - which is naturally another preparation and retrofitting for The Dark Knight's arrival
The story still ended up in a vat of chemicals and medications, but in a very different way. Kidnapped and beaten, Jack gets loose and fight off his perpetrators but ends up flushed with the chemicals used for the antiseptic drugs, ending up looking like a clown. What remained the same was that the first look of himself was what pushed him over the edge
Just two years later the origins were retconned yet again to reflect the Joker of The Dark Knight. In Brave and the Bold #31, The Arkham doctors want to save the dying Joker because they've sworn in oath to save lives, so they call upon the Atom to help with the procedure. The Atom doesn't want to help save the Joker's life because it's the Joker, yet he agrees to once he finds out that in trying to save the criminal, he very well might end up killing him. After the Atom is inevitably overcome by the Joker's firing brain synapses, the narrative weaves in and out of the villain's violent memories, with the Atom forced to experience the disturbing instances first hand. We see the Joker as a twisted child, who kidnaps local pets and kills them, we see him trapping his abusive parents in the house and setting it on fire,
The final, three-page sequence shows the Joker we all know and reveals/suggests that it is indeed the Joker from The Dark Knight
Jonathan Nolan: It grew from a little bit in part from a detail in The Killing Joke—the Allen Moore book—where he talks about if he had a past--he had to have a past--he’d want it to be multiple choice. And very much we sort of did a…felt like a little bit of a riff on that idea.(Collider.com)
In addition to Joker's preference of having multiple choice when it comes to his backstory, his name is also never revealed and his personal data is unknown, as it was in The Killing Joke which made that fact much more prominent.
While Bolland wishes Moore's story didn't reveal the origins and wishes Joker had a mystery about him, he acknowledges that this is not what actually happened in the comic books. The release and then the success of The Dark Knight prompted the changes in the comic books and numerous retconning and retrofitting but not only in comic books, but in some comic writers themselves. Jerry Robinson, who was one of the first employees of Bob Kane, claimed, post-The Dark Knight naturally, that Joker was always intended to be mysterious and unexplained. However, it is more than suspicious that he only mentioned it after nearly 60 years of character's existence and only after The Dark Knight's release and popularity of the movie's version of the Joker character, even thought he spoke about the character many times throughout the years even claiming its authorship.
Jerry Robinson: I decided to leave his face white simply because I wanted him to resemble the playing card joker. He didn’t have green hair. It was just the white of the face and the red lips. We decided deliberately not to explain it, not to write an origin. We thought that would detract from the whole aura, the mystery of the Joker – where did he come from, how did he get that way? No, we did not explain that, quite deliberately.(Comic Con panel 2009)
It is important to note that Robinson did not ended the relationship with Kane on a good note and Kane denied his claimed contributions to Joker's character. He stated that he only came up with Joker's card that they used for Joker and that Joker is a character based on The Man Who Laughs, a character Bill Finger pointed out and Kane drew. For their entire lives, the undisputed co-creator of Joker, Bill Finger, never mentioned any ambiguity or mystery about the character's origins once in his life, neither did the also undisputed co-creator Bob Kane. Finger actually wrote the origin story, something Robinson denies himself
Jerry Robinson: Well, we had a lot of discussions about that. Bill and Bob and myself, we discussed at my first outline of that first story how I was going to explain his visual look. (...) The origin story was written by a subsequent writer many years later.
Travis: So you and Bill did not drop the Joker in a vat of acid.
Jerry: ''No, we did not. Our initial reaction to that was if we dropped him into that vat, he obviously would have come out deformed.''
(Comic Con panel 2009)
This is one of the examples of why Robinson's credibility is shaken. Robinson could not have been developing Joker's look since Joker was basically the Conrad Veidt character drawn onto paper with no visual changes whatsoever, and its agreed by everyone involved that it was Finger who pointed out the Veidt character. Secondly, Robinson was a young employee of Kane whose job was lettering and backgrounds at the time Joker was developed, and Finger was the writer among few others. It was not Robinson's turf to characterize new characters. Another issue is that with that quote Robinson betrays his lack of knowledge of the development of the character, since the original Joker, like the Veidt character, had a frozen smile on his face aka was deformed this way by Gypsies. So he indeed was deformed after coming out of the vat. Third, he claims Finger did not write the origins yet he wasn't even working on this issue.Not only that, but he wasn't even working on Batman or DC for that matter at that point at all for years. He was gone before Joker's origins were written. He left in 1946 while the origins were written in 1951. Besides, Jonathan Nolan himself confirmed he came up with the ambiguous nature for Joker, it wasn't something from the comic books
Today, the Joker's bio on the official DC website recognizes the multiple choice angle as canon, and the bio was co-created by the big fan of the idea , Brian Bolland. It is interesting to note that the bio shows 3 "possible" origins, but two of them are one and the same and two of them come from the comics while one comes from the 1989 movie. It does recognize the part about the factory accident
Both the Multiple Choice approach and the established origins were great and worked just perfectly for their particular portrayal of the character in Batman and The Dark Knight.
'It may be significant that so many villains first arrived on the scene the way Joker had, without origin stories. They were granted the courtesy of being accepted as what they had chosen to become' (Batman: The Complete History).
In short, no villain had origins at first, nor there was even any kind of hint of any intended ambiguity. About 2 years into the series, it started changing more and more into the adventure series and shed more light on characters, their intentions, motives, stories and character traits and developing relationships. Once that was established and the Batman series fully changed into a conventional adventure series, characters were being more crafted and backstories were given to them.They started to appear in late 40's and Joker's turn came in 1951's Detective Comics #168, written by the co-creator of the character Bill Finger and with artwork credited to Bob Kane, also a co-founder.
In this issue, Batman and Robin are asked to be guest instructors at the University's criminology course. After lying out some background for good detective work and getting to know the students, he gives assigns them a 10 year old case even he couldn't figure out. An identity of a masked villain called Red Hood who disappeared without any trace
When Batman finally encounters the Red Hood during a robbery, the villain appears to be quite cocky and makes it clear that thanks to his disguise his identity will remain a complete mystery.
Red Hood makes an escape and the reports about new robberies committed by him reach Batman. A month later, Red Hood gets cornered by Batman and escapes seemingly sacrificing his life. He was presumed dead but the body was never recovered
One of the boys named Paul helped them solve the mystery and revealed that the Red Hood was a lab worker trying to steal $1 Million in a card factory to retire forever. After his dive into chemicals, he became disfigured and his skin and hair were permanently dyed - introducing The Joker! It's important to note that it was his physical appearance that pushed him into madness and made him decide upon his new image/identity
While his craziness, name and colors were explained, the frozen grin on his face wasn't addressed. To read more about Joker's frozen face and the origins behind the idea read The Complete Joker History article. Hi real name and pre-Joker identity remained unknown for the readers, aside from the fact that he was a lab worker
The origins were now set for Joker like for other villains and remained untouched for decades. In 1980's The Untold Legends of Batman, they were once again revisited by the 80's audience. In this issue, written by Len Wein and illustrated by Jim Aparo, the story remained consistent and unchanged
From mid to late 80's DC released an Official character guide called " Who's Who in DC Universe" which collected all the info and character traits in a encyclopedia-like style for every major character in DC. Joker's entry recalled the old known canonical origins
In 1988 Alan Moore decided to retell the origins but at the same time expand in the areas that weren't touched upon previously. Moore was sure not to contradict the established canon since he himself doesn't like inconsistencies in established canon
And the Joker's origin? Had he had one before that?
Alan Moore: He'd got a kind of muddy kind of origin. They'd said that he'd been the leader of a criminal gang called the Red Hood Mob and that while trying to escape from Batman he'd swum across this river of chemicals. And that was about it?
AM: That was about it and this was from a story from, like, the late '50s or something and so I thought "Okay, I won't contradict that," because I kind of believe in working by the rules of the material as it already exists but I can put a lot of spin on that. (Barry Kavanagh int., 2000)
While trying to stay true to the established origins as possible, he build the character behind the mask from scratch and infused it him with deep story and pathos, as he usually did with his characters, yet still preserving the fact that the young man worked at some point in the lab/factory. The pre-fall Joker was now a struggling young comedian who had trouble making ends meet and supporting his pregnant wife.
The reality of life has gotten hold of him, and he decided to cross the line and help with a robbery. The two gangsters that hired him made him assume the identity of a known robber Red Hood, which is just an identity assigned to different people, not a single gang leader as Police and Batman thought. While still not sure about this move, he wants to do it just for his pregnant wife, yet finds out she dies in an accident the night of the robbery, but there's no turning back with the gangsters.
From Batman's POV, Red Hood got caught by surprise,"his" thugs get killed and the panicked Hood makes a shocking move by jumping into the river where toxic wastes are emptied.
And again, it's the first look at his new appearance that triggers his madness
There's a misconception that the story Moore presents in The Killing Joke is not a real story of Joker but merely a figment of Joker's imagination. There's no indication that the flashback story that is intercut with the current story isn't true. The only line that can be taken as an argument is Joker saying that he prefers to have a multiple choice when it comes to his backstories, yet he also says that he does not remember his past so there's no assumption that the flashback story is him remembering.
It's rather a separate story , poetically and appropriately intercut within the contemporary story of Joker kidnapping Gordon's daughter. Then there's the fact that for decades Joker's origins were set in stone and were not contradicted by Moore, who even said himself that he doesn't like inconsistencies with previously established canon. And then you have Moore talking about infusing the character with pathos and dramatic story. It wouldn't not be so if the flashback was merely a made up figment of Joker's imagination, because the pathos given to the character would just go out the window as part of that imagination.
You made the villain such a pitiful figure. In the comics for years, he was a psychotic maniac who kills indiscriminately, just does terrible, terrible things, and you made him so pitiful and sad.
Alan Moore: I suppose that's what I was saying. Well, psychotic murders -- the key word there is "psychotic," which is, as far as I know, an illness. This is not to say that people shouldn't be entitled to feel rage or the lust for revenge when something happens to them at the hands of somebody like this, but you've got to remember at the end of the day it's not strictly speaking that person's fault. That something has happened to them, they have made some bad decision in their life, and while all of us are responsible for our actions, sometimes people get broken and it is increasingly difficult for them to know their own actions. So I suppose that if there was anything actually being said in "The Killing Joke," it was that everybody has probably got a reason for being where they are, even the most monstrous of us. (salon.com, 2009)
On top of all that, Moore has never ever hinted or undermined the legitimacy of the flashback story. And most importantly, the flashback story has been confirmed in past issues multiple times, which is going to be addressed in the article later.
The one who actually originated the retrofitting idea that the flashback story isn't true (at the same time acknowledging it was meant to be and disliking the fact) was the artist Brian Bolland.
It's important to note that he was not the storywriter and that he stated so only at the time of the release of The Dark Knight when DC was heavily pushing the angle that the movie was taking, which was to have Joker's origins ambiguous or purposefully unknown, which was an idea which originated solely from the sentence Joker said in The Killing Joke. It's also worth noting that Bolland statement was in The Killing Joke's rerelease in 2008, the same rerelease which changed the colors of Joker's outfit to match Heath Ledger's suit and added black around Joker's eyes and removed the yellow from Batman's emblem. Point being, the rerelease was clearly altered so it would match the movie, and so was Bolland's idea of discarding the origins which are actually shown to preserve the multiple choice angle the movie took.
One should also have in mind that aside form the idea being appealing to David Goyer and the Nolan Brothers, it would nullify the long established Joker origins involving permanent white skin which Nolan did not want to use in order to fit the character into our real world. By undermining the credibility of the origins, it erases them as canon in public's eyes and leaves a blank card for the filmmakers
........................................................................
The 1989 Batman deviated from the story a bit. Michael Uslan, producer: After much discussion, it was agreed that for the movie the Red Hood storyline would be too confusing, time-consuming, and unnecessary to include in the film. There was no compelling reason to add a third identity to The Joker. And so, it was Jack Napier who took the plunge into the vat of chemicals, not the Red Hood.(BITF 2002)
Joker still is born out of a criminal falling into vat of chemicals that emptied into the river, but the pre-Joker character was different.
He wasn't a robber but a mob hitman instead who already had psychological issues and was a multiple murderer who was doing hits for the mob for many years. According to the filmmakers in Shadows of the Bat documentary, they decided that it wasn't believable that a person can be so evil just by falling into chemicals. The fall has to have been the triggering mechanism to release or amplify an inner madness.
As in the comics, it was the first sight of his altered look that does the trick, and as in The Killing Joke, he just breaks laughing once he sees himself
The name Jack Napier was adapted into comics and written stories beginning with Dennis O'Neil's story "Images"
........................................................................
The first time Moore's story was referenced was in 1990's Batman #450. In this issue, after getting seriously injured Joker actually regains his sanity and recalls his entire life alone in the room while struggling with his confusion about what to do next and which road to take
In the following issue, Batman #451, it was Batman who was recalling the story presented by Moore. The Killing Joke's flashback story was now confirmed to be a part of canon continuity and the real event that really happened
The next reference/recollection to Moore's story was in 1993's Legends of the Dark Knight #50, written by Dennis O'Neil. In this issue it was Batman in disguise who recognized Joker by his voice and recalled what happened with Red Hood who jumped into the toxic river in panic
In 2004's Batman: Gotham Knights #54 Moore's story was not only recalled but also expanded and continued. A witness comes forward who knows that the comedian's (named Jack Napier in comic books since 1993) wife was actually killed to look like it was accident by the same mob that was trying to get him to participate in the factory robbery.
In this issue Joker gets the name of the man who killed his wife
Ironically, while some of other villains' origins were changed throughout the years like Catwoman's, Joker was the one whose origins remained so consistent for so many decades. It was until 2008, the release year of The Dark Knight and the year where DC started pushing the multiple choice theme and undermine the credibility of Moore's story, that Joker's origins were remade. It was in Batman: Confidential #9 where we get to meet a bored criminal named Jack who wants to face Batman one day. When he actually does, Batman throws Batarang to stop him from escaping and cuts his face leaving a Glasgow smile - which is naturally another preparation and retrofitting for The Dark Knight's arrival
The story still ended up in a vat of chemicals and medications, but in a very different way. Kidnapped and beaten, Jack gets loose and fight off his perpetrators but ends up flushed with the chemicals used for the antiseptic drugs, ending up looking like a clown. What remained the same was that the first look of himself was what pushed him over the edge
Just two years later the origins were retconned yet again to reflect the Joker of The Dark Knight. In Brave and the Bold #31, The Arkham doctors want to save the dying Joker because they've sworn in oath to save lives, so they call upon the Atom to help with the procedure. The Atom doesn't want to help save the Joker's life because it's the Joker, yet he agrees to once he finds out that in trying to save the criminal, he very well might end up killing him. After the Atom is inevitably overcome by the Joker's firing brain synapses, the narrative weaves in and out of the villain's violent memories, with the Atom forced to experience the disturbing instances first hand. We see the Joker as a twisted child, who kidnaps local pets and kills them, we see him trapping his abusive parents in the house and setting it on fire,
we see the first traces of his philosophy and the rise of his criminal career.
The final, three-page sequence shows the Joker we all know and reveals/suggests that it is indeed the Joker from The Dark Knight
........................................................................
The Multiple Choice theme introducing the mystery and ambiguity of Joker's origins is inspired solely from one panel of one comic book, which doesn't take anything away from the concept, however the fact remains that it was The Dark Knight that introduced the concept and it was never that way in the comic books. Still, it makes no impact on how well the idea worked for the new portrayal of Joker in The Dark Knight, nor does it take away anything from the comic book origins that were established in 1951 by the character's creators and survived for nearly 5 decades. Jonathan Nolan pretty much confirmed himself that the ambiguous origins for Joker was an idea he and Goyer invented, inspired by that one line from The Killing Joke.Jonathan Nolan: It grew from a little bit in part from a detail in The Killing Joke—the Allen Moore book—where he talks about if he had a past--he had to have a past--he’d want it to be multiple choice. And very much we sort of did a…felt like a little bit of a riff on that idea.(Collider.com)
In addition to Joker's preference of having multiple choice when it comes to his backstory, his name is also never revealed and his personal data is unknown, as it was in The Killing Joke which made that fact much more prominent.
........................................................................
While Bolland wishes Moore's story didn't reveal the origins and wishes Joker had a mystery about him, he acknowledges that this is not what actually happened in the comic books. The release and then the success of The Dark Knight prompted the changes in the comic books and numerous retconning and retrofitting but not only in comic books, but in some comic writers themselves. Jerry Robinson, who was one of the first employees of Bob Kane, claimed, post-The Dark Knight naturally, that Joker was always intended to be mysterious and unexplained. However, it is more than suspicious that he only mentioned it after nearly 60 years of character's existence and only after The Dark Knight's release and popularity of the movie's version of the Joker character, even thought he spoke about the character many times throughout the years even claiming its authorship.
Jerry Robinson: I decided to leave his face white simply because I wanted him to resemble the playing card joker. He didn’t have green hair. It was just the white of the face and the red lips. We decided deliberately not to explain it, not to write an origin. We thought that would detract from the whole aura, the mystery of the Joker – where did he come from, how did he get that way? No, we did not explain that, quite deliberately.(Comic Con panel 2009)
It is important to note that Robinson did not ended the relationship with Kane on a good note and Kane denied his claimed contributions to Joker's character. He stated that he only came up with Joker's card that they used for Joker and that Joker is a character based on The Man Who Laughs, a character Bill Finger pointed out and Kane drew. For their entire lives, the undisputed co-creator of Joker, Bill Finger, never mentioned any ambiguity or mystery about the character's origins once in his life, neither did the also undisputed co-creator Bob Kane. Finger actually wrote the origin story, something Robinson denies himself
Jerry Robinson: Well, we had a lot of discussions about that. Bill and Bob and myself, we discussed at my first outline of that first story how I was going to explain his visual look. (...) The origin story was written by a subsequent writer many years later.
Travis: So you and Bill did not drop the Joker in a vat of acid.
Jerry: ''No, we did not. Our initial reaction to that was if we dropped him into that vat, he obviously would have come out deformed.''
(Comic Con panel 2009)
This is one of the examples of why Robinson's credibility is shaken. Robinson could not have been developing Joker's look since Joker was basically the Conrad Veidt character drawn onto paper with no visual changes whatsoever, and its agreed by everyone involved that it was Finger who pointed out the Veidt character. Secondly, Robinson was a young employee of Kane whose job was lettering and backgrounds at the time Joker was developed, and Finger was the writer among few others. It was not Robinson's turf to characterize new characters. Another issue is that with that quote Robinson betrays his lack of knowledge of the development of the character, since the original Joker, like the Veidt character, had a frozen smile on his face aka was deformed this way by Gypsies. So he indeed was deformed after coming out of the vat. Third, he claims Finger did not write the origins yet he wasn't even working on this issue.Not only that, but he wasn't even working on Batman or DC for that matter at that point at all for years. He was gone before Joker's origins were written. He left in 1946 while the origins were written in 1951. Besides, Jonathan Nolan himself confirmed he came up with the ambiguous nature for Joker, it wasn't something from the comic books
Today, the Joker's bio on the official DC website recognizes the multiple choice angle as canon, and the bio was co-created by the big fan of the idea , Brian Bolland. It is interesting to note that the bio shows 3 "possible" origins, but two of them are one and the same and two of them come from the comics while one comes from the 1989 movie. It does recognize the part about the factory accident
Both the Multiple Choice approach and the established origins were great and worked just perfectly for their particular portrayal of the character in Batman and The Dark Knight.