At least the studio audience is luckier than they were in The Dark Knight Returns. The host, on the other hand...
Todd Phillips' Joker loves its nods to other incarnations of the Batman franchise's beloved Clown Prince of Crime.
- The cinema has a poster for Excalibur and a marquee advertising Zorro, the Gay Blade, Blow Out, and Wolfen, which date the film's setting to 1981. Coincidentally or not, Batman v Superman: Dawn of Justice used the same Excalibur film/poster in the same way in its flashback opening with the Waynes going out of a cinema (which also takes place in 1981) right before Thomas and Martha get murdered and leave Bruce as an orphan.
- To Batman (1989):
- Arthur has a copy of the painting The Blue Boy
◊ by Thomas Gainsborough in his living room. In Batman, when Jack Nicholson's Joker crashes into the Gotham art gallery, one of his goons vandalizes that same painting with graffiti spray. - One set of Arc Words as well as the initial Tag Line for the film, "put on a happy face", is the closing line of The Joker's Smylex commercial.
- The '89 movie controversially made The Joker himself the killer of Bruce Wayne's parents, rather than a random petty crook. Here it's a random person again, but it happens during a riot Joker helped instigate (and is the reason the Waynes try taking a back alley) and doing it to emulate him, complete with a clown mask and quoting Arthur almost verbatim when shooting Thomas.
- It's even depicted in a similar Film Noir manner, with long shadows and slow-motion of Mrs. Wayne's pearl necklace coming undone.
- The police car that collects Arthur has the license plate 9189, an anagram of 1989, which could be another reference to Tim Burton's original.
- Arthur has a copy of the painting The Blue Boy
- To Adam West's Batman:
- When young Bruce is going to meet Arthur at the Wayne Manor gate, he's at his private outdoor playset and approaches Arthur after sliding down a fireman pole, like Adam West's Bruce Wayne would to get to the Batcave. (This has been confirmed by the director. See Word of God on the Trivia tab.)
- It also seems that Arthur's final Joker getup (slightly curly green hair, pointy smile makeup, green shirt collar and maroon suit)◊ owes more to the Cesar Romero version◊ than the usual bright-purple-and-orange comic book ensemble. Whether this is intentional or just outdoor lighting making red seem colder is unclear.
- Joker uses a Colt Detective Special through the film; the same gun, albeit an older model, was briefly used by Romero's Joker in season 2 of the 1966 series◊
- To The Dark Knight:
- Arthur asking, "Do I look like the kind of clown who could start a movement?" echoes Heath Ledger's Joker asking "Do I look like the kind of guy with a plan?".
- After killing Murray, Arthur gets up and and grabs a camera pointing it directly to his face to mockingly repeat Murray's sign off to the audience, which is reminiscent of Ledger's Joker doing the same at the end of his videotape message scene, demanding Batman to step up and challenge him.
- It's quite thematic that Joker labels himself as someone that Gotham deserves, as the famous The Dark Knight speech labels Batman as someone that Gotham also deserves.
- The camera angle and cinematography in the shot of Joker gleefully observing the riot he provoked inside the patrol car is very similar to the scene in which the Joker escapes the GCPD in The Dark Knight.
- What's the first thing Arthur says to her when Sophie is startled to find him in her apartment? "I had a bad day."
- Arthur mentioning a joke that only he and Bruce would get is a reference to the ending joke in The Killing Joke.
- Arthur's utterly horrific knock-knock joke has a very similar "punchline" to that in Arkham Asylum: A Serious House on Serious Earth:Comic: "Surprise! Your wife's dead and the baby's a spastic!"Movie: "It's the police, ma'am! Your son's been run over by a drunk driver! He's dead!"
- Joker's talk show appearance in the film is very clearly influenced by a similar scene in The Dark Knight Returns. Right down to it not ending well for the host or the people watching.
- In Dark Knight Returns, the Joker kills Dr. Ruth (yes, that Dr. Ruth) by giving her a toxic kiss. This is alluded to in the film when he greets a Dr. Ruth Expy with a big kiss on the lips, causing the host to ask if she's OK.
- The social worker Arthur sees twice in the film (before the department's funding is cut) is named Debra Kane — also the name of a Child Protective Services caseworker in the novel Batman The Ultimate Evil. A very fitting homage, given what we find out later about Arthur being abused as a child.
- One of the graffito seen in Arkham is a green question mark.
- While Arthur's clown designs have more makeup than the traditional appearance that the Joker has (with markings on his eyes and nose), the scene where he murders Randall features a visage very close to his comic book counterpart with the bright green hair and completely white face.
- The scene where Joker is about to come on Murray's stage is lit a very deep blue, making the suit look outright purple as it frequently is across media.
- Wall markings of the Amusement Mile, Gotham City's old amusement park in the comics, can be seen in the first set stills. As well as graffiti referencing the Mad Hatter.
- On Penny Fleck's psychiatry files from Arkham, it mentions her former doctor was Benjamin Stoner. In the comics, Stoner was one of the head doctors at Arkham Asylum who became an opponent of Doctor Fate known as Anti-Fate after being possessed by a Lord of Chaos.
- The "super-rats" segment on Murray Franklin's show and in the news references Ratcatcher, an obscure D-list villain who could mind control rats and later appeared in James Gunn's The Suicide Squad.
- Murray also jokingly says that the mayor's solution to the rat problem is "super-cats".
- Arthur takes a moment to enjoy a Charlie Chaplin film. The Joker, in most continuities, is a fan of classic comedians, with Chaplin being one of his favorites.
- The typeface font of Live! With Murray Frankin is the same one◊ used for the title of Batman: The Animated Series. The painted Gotham City background in Frankin's set is also modeled after the backdrops from The Animated Series.
- In the final scene, Arthur was being evaluated by an African-American female doctor at Arkham, who could be a nod to the Batman: The Animated Series character Dr. Joan Leland, another African-American female doctor at Arkham who was also notably responsible for bringing in Dr. Harleen Quinzel in the series finale episode "Mad Love" adapted from an Eisner Award-winning one-shot special-issue graphic novel of the show's tie-in comic The Batman Adventures, which leads to Harleen to first meet and fall in love with the Joker and caused her to become Harley Quinn.
- The rioters modeling themselves after Arthur/the Joker may recall the Jokerz from Batman Beyond, gangsters (many from poorer backgrounds) who emulate the Joker in admiration of him.
- Joker's red suit in this movie resembles Jeremiah's first suit, pre-insanity gas, from Gotham. It also brings to mind Jerome's carnival suit as well.
- Arthur's laughing fits often leave him struggling to breathe, similar to how Joker's laughing gas works.
- Randall and Gary could be seen as a reference to how in the comics The Joker often likes to employ Fat Bastards and Depraved Dwarfs as his henchmen.
- This is not the first time the Joker's real name was said to be "Arthur". In issue #5 of his short-lived ongoing in the '70s, he posed as the long-lost great-grandson of a famous painter, who was named Arthur Wilde, claiming to his henchmen that it wasn't just a scam and that he really was Arthur Wilde. (At the end of the issue he confesses that he lied.)
- Mixed with Call-Forward, Arthur's failed attempts to amuse Bruce and get him to smile calls to mind one reason for the Joker's obsession with Batman: he wants to make him laugh.
- When Arthur is standing triumphantly surrounded by his mob of admiring rioters, what are several of them wielding, prominently visible right behind him? Bats.
- The Joker being a terrible comedian is a common theme, notably The Killing Joke, Batman Beyond: Return of the Joker, and Death of the Family.
- Arthur possibly being the estranged son of Thomas Wayne is similar to the Boomerang Killer from World's Finest #223, who also suffered head trauma and spent time in an asylum.
