Trivia: Murray Franklin's show is, as displayed on the TV in the hospital, on channel 3, the same channel The Jerry Langford Show was in King of Comedy. (00:59:25)
Trivia: The news says something about giant rats around the city. While Arthur is talking with his boss on the phone on the street around the corner a big rat passes by (00:28:55). The rats appear also by the garbage bin when Arthur walks past the dead Wall Street guy (00:34:05) and when Bruce is crying over his dead parents (1:53:30).
Trivia: The detectives who are investigating Arthur throughout the movie are Detective Garrity and Detective Burke. In "The King of Comedy", inspiration for this movie, Rupert Pupkin was investigated by inspector Gerrity and Captain Burke.
Trivia: The sequence of the Joker killing a person on TV was also seen in Frank Miller's graphic novel The Dark Knight Returns.
Trivia: Arthur's dressing room for the talk show is 404. Batman #404 was the first section of the Batman: Year One storyline, covering the early days of Batman's crime fighting.
Trivia: Brett Cullen (Thomas Wayne) played a small role in The Dark Knight Rises.
Trivia: Arthur's joke "When I was a little boy and told people I was going to be comedian, everyone laughed at me. Well no one's laughing now" is a near-direct copy of a joke from late British comic Bob Monkhouse.
