Kane noted how the playing card looked like Conrad Veidt, who played a man with a freakish perma-grin in the 1928 German Expressionist film The Man Who Laughs. Kane denied this, saying that Robinson’s card was merely a place holder. The real Joker, Kane claims, was inspired by Veidt after Finger pointed to a picture of him and said, “Here’s The Joker.” Regardless of who officially merits credit for the character’s inspiration, the creation of The Joker was a team effort, from three hall-of-fame comic book guys.

“Serpico” (1973) Sidney Lumet’s 1973 crime drama “Serpico” stars Al Pacino as New York Police Department officer Frank Serpico, whose undercover mission to expose corruption within the NYPD made him a whistleblower with a target on his back. Pacino was Oscar nominated for the role, while Lumet’s grounded realism was championed for giving the film a lived-in, visceral tone. The latter of which is a top priority for Phillips in “Joker.” The director said part of his pitch for “Joker” was telling Warner Bros. that he was making a 1970s character study like “Serpico,” but dressed up as a 2019 comic book movie.

Joker ends with yet another version of the Wayne family’s murder. As always, they are seen exiting a movie theater which, in this case, is screening the action comedy Zorro, The Gay Blade starring George Hamilton. Most tellings of Batman’s origins involve the Waynes going to see a Zorro movie on the night of their deaths — which is often used to partly explain where Bruce gets the idea of avenging their murders by wearing a dark costume and hiding his identity. Given Joker’s setting in the early 1980s, Zorro, The Gay Blade, which was released in 1981, makes perfect sense to be playing in Gotham City on that fateful night.

The other Scorsese touchstone in Joker is 1983’s The King of Comedy, about an aspiring comic (De Niro) who fantasizes about becoming famous as a guest on a late night talk show. Like the Joker, De Niro’s Rupert Pupkin initially experiences delusions of appearing on his favorite TV show, then makes that dream into a reality. (Or perhaps he is driven so insane he can no longer distinguish between reality and fantasy.) More King of Comedy homages in Joker: Both characters rehearse their TV appearances alone in their houses, both use acts of violence to fulfill their dreams of stardom, both become celebrated by the public despite their immoral acts, and both still live with their mothers.

Joker’s structure leans very heavily on two different Martin Scorsese films. The first is Taxi Driver, the 1976 movie about a loner named Travis Bickle (Robert De Niro, who co-stars in Joker) who slowly succumbs to loneliness and madness before going on a mass killing spree. Besides the generally similar story arc here are a few more details the two films share: Both protagonists write their dark thoughts in journals, both fixate on powerful political figures, both have delusional thoughts that make it tough to tell whether every moment onscreen is really happening, both characters completely change their physical appearance as part of their mental breakdown, and both characters mime blowing their own brains out by pointing finger guns at their temples.