Rather than dubbing in the gunshots during the bank robbery shoot-out, Michael Mann had microphones carefully placed around the set so that the audio could be captured live. This added to the impact of the scene, because it sounded like no other gunfight shown on-screen.
In an interview with Al Pacino on the DVD Special Edition, Pacino revealed that for the scene in the restaurant between Hanna and McCauley, Robert De Niro felt that the scene should not be rehearsed so that the unfamiliarity between the two characters would seem more genuine. Michael Mann agreed, and shot the scene with no practice rehearsals.
Val Kilmer was thrilled to learn that the moment in the gunfight scene where he runs out of bullets, and rapidly changes his magazine, is regularly shown to Marine recruits as an example of how to perform the action properly. According to Kilmer, a trainer once said, "If you can't change a magazine as fast as this actor, get out of my army!"
In an early draft of the script, Vincent Hanna had a cocaine habit, which, according to Al Pacino, explains his bombastic outbursts.
When Kevin Gage was imprisoned for two years in 2003, he was universally addressed by fellow inmates and prison guards as "Waingro", his character from this movie.
Tom Elfmont: The concierge at the airport hotel is played by a former L.A.P.D. detective, who served as one of the film's technical advisers.
Michael Mann: [time is luck] The catchphrase "time is luck" is used by McCauley when talking to Eady about their relationship and having time for them. (It is also used in El sabueso (1986) when Molly talks to her husband, Will Graham, and Miami Vice (2006), when Isabella is talking to Sonny about their relationship.)
Michael Mann: [military training] Neil's crew shows evidence of military training when attempting their heists.
Michael Mann: He disowned the television version aired by NBC. Mann offered to restore seventeen of the cut minutes, NBC decided to instead cut forty minutes of the film out, in order to fit a three-hour television time slot. Mann said, "You can call it a Michael Smithee or an Alan Mann movie."