In a Deleted Scene, Frank gets a shave at a perfume shop. Henry Fonda sits in the same position he did in My Darling Clementine. At the end of the film, he wears a similar outfit to the one he wore in Warlock. The latter film also contains a sequence in which Fonda's character kicks a crippled man off his crutches, as Frank does to Mr. Morton.
Executive Meddling: Paramount left Sergio Leone alone during the actual production, but they cut over 20 minutes of the film for international distribution, including the entire tavern sequence and Cheyenne's death. This accounted in large parts for the film's cool reception upon release. Nor would West be Leone's last brush with studio editors, either.
Fake American: Jill is played by Claudia Cardinale and Morton by Gabriele Ferzetti (both Italian).
Fatal Method Acting: Al Mulock, a Canadian actor playing one of the gunmen in the opening scene, committed suicide by jumping out a window (in costumes) between takes.
Playing Against Type: Henry Fonda plays the villain in this one, and a very vile one. Fonda had intended to radically change his usual appearance for the film, growing a mustache and beard and wearing brown contact lenses. Leone talked him out of it, as the shock of seeing good old Henry Fonda as a villain was exactly what he wanted. Ben Mankiewicz remarked on TCM that casting him as the villain hurt the box office, because viewers, especially Americans, thought he was too creepy.
Orphaned Reference: Harmonica has scars on his face at one point. This is from a deleted scene where he was beaten up by the sheriff.
Carlo Ponti wanted to produce the film with his wife Sophia Loren playing Jill.
Eli Wallach was meant to play Cheyenne, but Leone felt that he was too recognisable after The Good, the Bad and the Ugly. Again, he would have been a Mexican bandit, but this was changed when Jason Robards was cast. That's why Cheyenne, despite his American accent, speaks like English isn't his first language.
Kirk Douglas, an admirer of Leone, lobbied for the role of Cheyenne.
Leone asked Robert Ryan to play the Sheriff of Flagstone. Ryan declined, preferring to film The Wild Bunch instead.