Writer Alan Trustman got the idea for the film when he was working in a bank and spent his more idle moments imagining how to rob it.
Of all of the films that Steve McQueen made in his career, this is reported to have been his favorite.
According to Norman Jewison, the initial bank robbery was filmed at the downtown branch of the National Shawmut Bank, and that although the guards and bank officials knew what was going on, the customers did not because the filmmakers were using a concealed camera. Although they apparently thought that a real robbery was occurring, none of the customers or pedestrians interfered in any way.
After watching a five hour rough cut of the film, composer Michel Legrand took a six week vacation during which he wrote 90 minutes of music. The film was then reedited to the music, instead of the other way around. If this experiment had failed, Legrand would have written a second score in the traditional way free of charge.
The polo match was partially filmed by mounting a camera onto a chest harness on one of the players.