McQueen was widely known as a tremendous motorcyclist and racecar driver.
When insurance companies for the films allowed, he would perform many of his own stunts.
His most famous stunts were performed in The Great Escape where he did much of the bike riding and Bullitt where he did much of the driving. Much to his dismay, the insurance companies would not allow him to perform the most dangerous stunts in either film which he always regretted. Contrary to popular belief, McQueen did not perform the the famous fence jump in The Great Escape. Instead his good friend and stunt driver Bud Ekins made the jump.
Steve always made a point to credit Bud Ekins for the jump whenever asked about it during interviews. There were many times someone would say
"That was a GREAT jump!" and he would say "Yeah, it was but I didn't make it."
Video: Steve McQueen
Despite being depicted as the factory backed Ferrari team, the 512's used were borrowed from Belgian Ferrari distributor Jacques Swaters. Enzo Ferrari had been approached to supply the cars but refused official Ferrari participation after reading the script and finding out that the movie ends with a victory for Porsche. Enzo told the producers they could only use the factory 512's if the script was re-written to have a Ferrari win the race. His request was refused.
McQueen had wanted to employ Christopher Chapman's new multi-dynamic image technique in the film, as had been done at his instigation with The Thomas Crown Affair, in which he starred in 1968. Chapman advised against it, much to McQueen's disappointment; in Chapman's words, “it was much too big a film, with too many writers; it wouldn't work that way.”