The Academy Award-winning song "The Windmills of Your Mind" from this movie is sung by actor Noel Harrison, son of Rex Harrison.
Legendary documentary filmmaker Frederick Wiseman reportedly wrote one version, or contributed to screenplay of this film, without any on-screen credit.
Of all of the films that Steve McQueen made in his career, this is reported to have been his favorite.
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 sailplane (N9860E) that Steve McQueen flies early in the movie is a Schweizer SGS 1-23H-15. It is still in use in New York.
Sean Connery had been the original choice for the title role but declined, a decision he later regretted.
The one-minute kissing sequence between the two leads took eight hours to film over a number of days.
The bank robbery was filmed with hidden cameras that only the crew, guards, and tellers knew about.
In the movie, the Ferrari driven by Faye Dunaway and being referred to as "one of those red Italian things" is actually the first of only ten Ferrari 275 GTS Spyder NART, serial number 09437. This particular car came second in its class in the 1968 12 hour of Sebring before being repainted and used for the movie. Steve McQueen liked the car so much, he wanted one for himself. He eventually ended up with serial number 10453. That car is today with collector Anthony Wang in NY, USA.