Although the film received mixed reviews, Akira Kurosawa was so impressed he sent John Sturges a ceremonial sword as a gift.
Yul Brynner had a major say in casting decisions. He specifically requested that Steve McQueen be cast as Vin Tanner. Brynner later regretted the move because he and McQueen became enemies on set.
The one-upmanship between Yul Brynner and Steve McQueen spread to the other actors, and they all started pulling stunts of their own in order to get the audience's attention. While a lot of the attention-hogging made the finished film, John Sturges was terrified by how quickly he lost control of his cast.
The "bandit gang" hired for Calvera adopted Eli Wallach as one of their own. In the mornings before shooting started, but after Wallach was in costume, he and the group would go riding together for an hour. Additionally, members of the gang insisted on doing the final checks for Wallach's horse tack and prop gun before he was allowed to use either.
In 1980, Steve McQueen, who was dying of cancer, called Yul Brynner to thank him. "What for?" asked Brynner. McQueen replied "You coulda had me kicked off the movie when I rattled you, but you let me stay and that picture made me, so thanks". Brynner told him, "I am the king and you are the rebel prince; every bit as royal, and dangerous to cross." McQueen said, "I had to make it up with Yul 'cause without him I wouldn't have been in that picture."