During the editing process, two reels of footage from the Liberty Parade sequence were stolen and were never to be seen again. This meant that the scenes had to be reshot at a cost of $750,000. Cinematographer Vilmos Zsigmond was no longer available, so he was replaced by László Kovács.
The idea of a man discovering a crime by listening to a recording is a reinterpretation of Michelangelo Antonioni's film Blowup (1966), but using sound instead of photographs.
The accident at the start of the film alludes to the Kennedy incident at Chappaquiddick.
Also alludes to the Watergate scandal and the JFK assassination.
John Travolta suffered from insomnia during the shoot. His lack of sleep helped him create a very moody performance and is why his character seems so downtrodden throughout the movie.
Al Pacino was De Palma's first choice for the role of Jack Terry. When he proved unavailable Travolta was signed, prompting a suggestion from at least one studio executive to cast Olivia Newton-John in the role of Sally (which De Palma refused).
Quentin Tarantino stated in an interview that this film is his most favorite 'Brain De Palma' movie ever. In fact, Tarantino casted John Travolta in Pulp Fiction (1994) because he liked his performance in this movie so much.