When Warner Bros. announced a new movie about the Joker starring Joaquin Phoenix, fans became curious. To call the Joker's comic book origin debatable would be an understatement. How do you make an origin story for a character who seems to manufacture new backstories from story-to-story? While everyone knows Batman is Bruce Wayne, and he started fighting crime when his parents died, comic book fans aren't even sure of the Joker's real name, let alone what turned him into the Clown Prince of Crime.
He has done everything from becoming a mafia tough guy to the head of his costumed gang to a struggling comedian pushed to the brink of insanity. Which version of the Joker origin will Todd Phillips adapt into a gritty crime drama? Will it be one of the gory tales from Joker history where he kills his family? Or will The Killing Joke prove most influential, as it's arguably the most iconic Joker story ever written? The director will have plenty of options for his take on the Joker's origin, and he could always add a twist to the villain's knotted and mysterious backstory.
The Joker's connection to the Red Hood goes back to 1951 and Detective Comics #168. Some consider this origin story the closest to official canon in DC's comics, and some version of these events pop up when retelling the character's backstory, albeit in different ways. The Detective Comics' version of events starts with a villain named Red Hood who wears a red cylinder outfitted with a two-way mirror system and a gas mask over his head. He wants to get out of the crime game once and for all, so he sets a goal for himself: make $1 million and call it a day.
During one final heist at the Monarch Playing Card company, Red Hood runs into Batman. Rather than go to jail, Red Hood escapes through a river of chemical waste running under the factory. Back at his hideout, Red Hood realizes his hair has turned green, his lips were “rouge-red,” and his skin “chalk-white.” Instead of quitting crime, Red Hood rebranded as the Joker and started on the path to comic book history.
In Alan Moore's genre-defining The Killing Joke, the Joker's backstory unravels in a series of flashbacks to show his life before turning into a criminal mastermind. The Joker, or "Joe" as he's known in the flashbacks, starts out as a washed-up comedian who spends his nights trying to scrape together enough money to support his pregnant wife and himself. To make quick cash, Joe takes a job with the mafia while impersonating the Red Hood and robbing the Monarch Playing Card company.
Prior the job, Joe discovers the death of his wife and unborn child and tries to back out. The mafia forces him to go on the job, and he runs into Batman before falling into the river of toxic waste below the playing card factory. He loses his mind as he's washed to shore, emerging from the water as a green-haired agent of mayhem. Initial reports indicate this version of events may influence Joaquin Phoenix's Joker movie, but it likely won't resemble a straight Killing Joke adaptation, based on other casting details.
The Brave and the Bold #31 forges an entirely different origin for the Joker, dating all the way back to his childhood, and mostly ignores any mention of the Red Hood. Accordingly, J. Michael Straczynski scripted a story where Joker is dying from a neurological disease, and the Atom has to come into Arkham Asylum to administer an experimental medicine to save the villain's life. While inside the Joker's brain, the Atom gets shocked by neurological lightning and begins to experience the Joker's memories. He sees the Joker as a child psychopath who tortured animals and beat up would-be bullies on the playground before burning his house down, presumably killing his parents in the process.
As the Atom experiences one of Joker's kills, the madman explains he doesn’t want to change to fit into the world - rather, he wants the world to change, so it fits him. While the new movie might not go this far into the Joker's youth, this philosophy could fit in with a gritty exploration of what makes a madman tick.
"Case Study," from 2003's Batman Black and White Vol: 2, tries to apply a method to the Joker's madness by combining all of his histories into one short story. The comic begins in medias res (in the middle of the action) as the Joker shoots up one of Gotham's many high-society functions. Batman quickly captures and brings him back to Arkham Asylum. From there, a pair of doctors discuss whether or not the Joker is insane or if he's merely pretending. The two doctors go through the Joker's file and find he got his start as a regular thug who took over a gang with his "cunning mind, melded with a sadistic streak." After he grows bored of being on top, he invents the Red Hood persona so he can front a second gang to get his hands dirty.
The Monarch Playing Card heist plays out as usual, with Batman catching him in the act, and Red Hood diving into the toxic waste below the factory. While it's canon to say this turned Joker crazy, a doctor in "Case Study" believes his new look made him more sane and focused than before. Though he acts irrationally as the Joker, it's in a way that suggests meticulous research on his part. Unfortunately, this diagnosis loses its authority when it turns out a young Harley Quinn wrote the report.