The young man with the transistor radio is played by Our Gang/The Little Rascals graduate Carl 'Alfalfa' Switzer in his final screen appearance before his untimely death in a shooting incident.
Co-writers Nedrick Young and Harold Jacob Smith were cast as the prison truck drivers, with the writing credits below their faces, because Young was blacklisted and writing under a pseudonym at the time, and producer Stanley Kramer wanted to identify them truthfully.
Robert Mitchum turned down the role of John "Joker" Jackson (Tony Curtis' role). Mitchum, who claimed to have served on a Southern chain gang when he was 14, said that he didn't believe the premise that a Black man and a white man would be chained together, as such a thing would never happen in the very-strictly-segregated South. Over the years, this reason was corrupted to the point where many people believed Mitchum turned down the role because he didn't want to be chained to a Black man, an absolute falsehood. Curtis repeated the inaccurate story in his autobiography, but recanted after it was explained to him.
Charlie Potatoes is an old slang term (more common in the U.S. than the U.K.) for someone who is on top of the world, usually in terms of money or popularity.
Despite the mutual admiration and camaraderie among the cast and crew, the film wasn't necessarily a breeze to shoot. It was physically exhausting for Tony Curtis and Sidney Poitier, who had to run through fields, swamps, and woods and fight each other bare-fisted, all while being chained together. There was also the famous climactic run for the train. Most grueling of all were the scenes where the two chained men are swept down the rapids of a river and their desperate attempt to climb out of a deep clay pit during a rainstorm. Curtis said there were no doubles for the clay-pit scene, which he deemed the hardest sequence in the film. He also said he had a stunt double for some of the water scenes while Poitier had a dummy as a stand-in for at least one shot. However, most of the grueling stunt work was done by the two stars.