While filming the white water canoeing scene, Ned Beatty was thrown overboard and was sucked under by a whirlpool. A production assistant dove in to save him, but he didn't surface for thirty seconds. Sir John Boorman asked Beatty, "How did you feel?," and Beatty responded, "I thought I was going to drown, and the first thought was, how will John finish the film without me? And my second thought was, I bet the bastard will find a way!"
This is the movie Burt Reynolds appeared in as opposed to Il padrino (1972). He was being considered for the part of Michael Corleone, but Brando said that "if Burt Reynolds is in my movie, I will quit."
To minimize costs, the production wasn't insured, and the actors did their own stunts. Jon Voight climbed the cliff.
Burt Reynolds broke his coccyx (tailbone) while going down the rapids when the canoe capsized. Originally, a cloth dummy was used, but it looked too fake, like a dummy going over a waterfall. Legend has it that when Reynolds approached Director Sir John Boorman after the incident, he asked: "how'd it look?" To which Boorman replied: "It looked like a dummy falling over a waterfall."
According to director Sir John Boorman, the gas station attendant's jig during "Dueling Banjos" was unscripted and spontaneous.