According to Gregory Peck, director William Wyler intended the film to be a left-wing allegory for the Cold War. Peck believed the United States should have retained good relations with the Soviet Union and China after World War II.
Gregory Peck and William Wyler had become friends a few years earlier and got on well while making Roman Holiday (1953), but they clashed repeatedly during filming. After Peck stormed off the set one day following a blazing row, Wyler told the press, "I wouldn't direct Peck again for a million dollars and you can quote me on that." They reconciled a year later but true to the director's word Wyler and Peck never made another film together.
Charlton Heston initially turned down the role of ranch foreman Steve Leech because he didn't think the part was big enough. His agent convinced him that it would be worth it just for the opportunity to work with Gregory Peck and William Wyler.
Jean Simmons was so traumatized by the experience making the film that she refused to talk about it for years until an interview in the late eighties when she revealed, "We'd have our lines learned, then receive a rewrite, stay up all night learning the new version, then receive yet another rewrite the following morning. It made the acting damned near impossible."
Charlton Heston recalled filming a scene with Carroll Baker, "I had to fight with Carroll in one of my scenes. It's actually one of the best scenes I was in. I've got a grip on her wrists, and she's struggling to get out of it. Willy gave me secret instructions not to let go of her. He told Carroll, 'Break loose, so you can hit him.' Well, I've got a big enough hand I could have held both of her wrists in one. We must have done - I don't know - ten takes, easy, on this shot. She's got sensitive skin and she's getting welts. Between takes they were putting ice and chamois cloths on her wrists. She was weeping with frustration and anger and all kinds of things. Finally she tells Willy, 'Chuck won't let me go.' And he says to her, 'I don't want him to. I want you to get away by yourself.' Christ, I outweighed her by nearly a hundred pounds.'
One of the actors who didn't have a problem with William Wyler was Burl Ives. He later said, "I found Willy delightful. I never got annoyed at him. I learned a helluva lot from him. He was enigmatic sometimes, but that's what he did to make me figure things out."
Tempers flared on the set between numerous individuals, particularly William Wyler and Charles Bickford, who had fought on the set of Hell's Heroes (1929) years before and were continuing their antagonistic relationship. Wyler liked to shoot numerous retakes and Bickford was very cranky, often refusing to say a line he didn't like or to vary his performance no matter how many takes he was forced to deliver.