Gene Hackman was not proud of his performance in the film, and admitted that he only took the role for the money.
Prisoners at the San Quentin Prison were actually paid to be extras and background artists in this movie.
After shooting at San Quentin State Prison, actor Mickey Rooney was presented with a plaque from the inmates with an engraved inscription thanking Rooney "for being such a nice human being".
Gene Hackman turned down roles in Jaws (1975) , One Flew Over the Cuckoo's Nest (1975), Network (1976), Close Encounters of the Third Kind (1977), and Apocalypse Now (1979) to appear in this, and March or Die (1977) for Lew Grade and A Bridge Too Far (1977) simply because a better paycheck was on offer.
Cinematographer Fred J. Koenekamp was injured in a vehicle accident during filming where a truck went around a bend heading straight for Candice Bergen, its door flying open, hitting the DOP and the low camera he was looking into. The rubber edges of the cam's viewfinder fortunately cushioned the blow on the eyes. Koenkamp had a concussion and required six stitches and could not complete working on the picture, he being replaced by veteran DOP Ernest Laszlo.