Steve McQueen wanted to act in this film but couldn't at first because the schedule of his TV series, Wanted: Dead or Alive, wouldn't allow it. He crashed a car and while he was "out sick", he shot this film.
George Peppard was first considered for the role of Vin.
Yul Brynner (5'10") was concerned to make sure he always appeared substantially taller than Steve McQueen (5'9 1/2"), to the point of making a little mound of earth and standing on it in all their shots together. McQueen, for his part, casually kicked at the mound every time he passed by it.
Yul Brynner had a major say in casting decisions, including the decision to cast Steve McQueen. He specifically requested that McQueen be cast as Vin Tanner. Brynner later regretted the move since he and McQueen developed a disastrous relationship on set.
Yul Brynner was married on the set; the celebration used many of the same props as the fiesta scene.
Robert Vaughn played the role of Lee in the film. He later came back to star in the TV series The Magnificent Seven playing Judge Oren Travis.
Walter Bernstein did the original adaptation of Akira Kurosawa's film (Shichinin no samurai) but it wasn't used. Walter Newman wrote the screenplay that is substantially what you see on screen.
Eli Wallach and Robert Vaughn are both killed in this film. In real life, however, they are the last surviving members of the main cast. Wallach is a fine example of irony, for although he played the villain and was older than almost all the other leads, he has outlived them all except Vaughn.
John Sturges faced a major problem during filming. The screenplay mentioned which of the Seven died, but in no order (the battle was not choreographed), and without being clear as to how. So Sturges came up with the idea to kill off the dying members of the seven in the order they had been cast, which went as follows: Lee (Robert Vaughn), Harry Luck (Brad Dexter), Bernardo O'Reilly (Charles Bronson), and Britt (James Coburn). Vaughn originally lobbied against dying first (because the character was especially created for him), so Sturges came up with a new solution, and the final death sequence which appears on film went as follows: Harry Luck (Dexter) is shot while riding back into town to join the seven who were holed up in the cantina, Lee (Vaughn) is shot after killing three bandits who were holding several villagers prisoner in a farmhouse, Britt (Coburn) is shot in the chest as he prepares to throw his knife and O'Reilly (Bronson) is wounded several times before this, but finally dies after being shot in the stomach while pushing the children to safety.
James Coburn (Britt) and Robert Vaughn (Lee) have only 11 and 16 lines in the entire film respectively. Although they were close friends for almost 50 years, this is their only film together.
James Coburn was a big fan of Shichinin no samurai and his favorite role in that film was the character that he ended up playing in the Americanized version.
James Coburn's friend Robert Vaughn recommended him to director John Sturges for the last remaining lead, the role of Britt. Sturges said he needed a Gary Cooper type of actor, and Vaughn said Coburn was the actor he needed.
Sterling Hayden was originally supposed to play the knife expert, Britt. Hayden dropped out for unknown reasons, so John Sturges sent out an extensive casting call. Robert Vaughn (Lee) recommended his old schoolmate and friend James Coburn for the role. Vaughn and Coburn helped each other get roles throughout the rest of Coburn's life.
Elmer Bernstein, whose score for this movie is one of the best-known ever composed, also wrote the score for the parody of this film, ¡Three Amigos!.
A young Gene Wilder auditioned for the role of Vin.
According to Eli Wallach's autobiography, Yul Brynner had a major problem with what he perceived as Steve McQueen's trying to upstage him. According to Wallach, McQueen would do things when on screen with Brynner to draw attention to his character. Examples were his shaking of the shotgun shells and taking off his hat to check the sun during the hearse scene and leaning off his horse to dip his hat in the river when the Seven cross into Mexico. Brynner was supposedly so worried about McQueen stealing his limelight in scenes that he hired an assistant to count the number of times McQueen touched his own hat when he Brynner was speaking.
According to a John Sturges interview given in 1990 for the book 'John Sturges, Stories of a Filmmaker' by Emmanuel Laborie, the music for the movie was to be composed by Dimitri Tiomkin. But the director had a quarrel with his favorite composer, because Sturges did not agree with a song during the opening credits, like in Gunfight at the O.K. Corral. Tiomkim dismissed and was replaced by Elmer Bernstein.
According to the DVD notes, both John Ireland and Sterling Hayden were approached for the role of Britt.
Body count: 55
Composer John Williams was a member of the orchestra that recorded Elmer Bernstein's score; he played the piano.