In Sir Michael Caine's opinion, Heath Ledger beat the odds and topped Jack Nicholson's Joker from Batman (1989): "Jack was like a clown figure, benign but wicked, maybe a killer old uncle. He could be funny and make you laugh. Heath's gone in a completely different direction to Jack, he's like a really scary psychopath. He's a lovely guy and his Joker is going to be a hell of a revelation in this picture." Caine bases this belief on a scene where The Joker pays a visit to Bruce Wayne's penthouse. He'd never met Ledger before, so when Ledger arrived and performed, he gave Caine such a fright, he forgot his lines.
In preparation for his role as the Joker, Heath Ledger hid away in a motel room for about six weeks. During this extended stay of seclusion, Ledger delved deep into the psychology of the character. He devoted himself to developing the Joker's every tic, namely the voice and that sadistic-sounding laugh (for the voice, Ledger's goal was to create a tone that didn't echo the work Jack Nicholson did in his 1989 performance as the Joker). Ledger's interpretation of the Joker's appearance was primarily based on the chaotic, disheveled look of punk rocker Sid Vicious combined with the psychotic mannerisms of Malcolm McDowell's character, Alex De Large, from Orange mécanique (1971).
While filming a chase scene on Lake Street, the Chicago Police Department received several calls from concerned citizens stating that the police were involved in a vehicle pursuit with a dark vehicle of unknown make or model.
This was the first comic book movie to reach the $1 billion mark worldwide.
The bus crashing backwards into the bank in the opening sequence was much harder to pull off than was anticipated. The bus had to be taken apart and reassembled inside the building (a disused post office), concealed behind a large false wall, and then propelled backwards with an air cannon.
Wayne Baker: The IMAX camera technician and consultant has a cameo that is the only close-up shot in the IMAX format in this movie. He sits on the loading dock and reacts to the Batpod emerging from the wreckage of the Batmobile.