It stars Henry Fonda, cast against type as the villain,[5][6] Charles Bronson as his nemesis, Jason Robards as a bandit and Claudia Cardinale as a newly widowed homesteader.

After directing The Good, the Bad and the Ugly, Leone decided to retire from Westerns and aimed to produce his film based on the novel The Hoods, which eventually became Once Upon a Time in America.

However, Leone accepted an offer from Paramount Pictures providing Henry Fonda and a budget to produce another Western.

McBain intended to profit by building a watering station on Sweetwater, because he knew the railroad from Flagstone would eventually pass through his property.

Harmonica saves Jill from two of Frank's men and spies out the railway carriage where Morton (owing to his spinal tuberculosis) is confined on crutches.

Cheyenne escapes custody and he and his gang engage Frank's remaining men in a gunfight on Morton's train.

Harmonica puts the body on Cheyenne's horse and rides off as Jill serves water to the railroad workers.

In addition to the credited cast, uncredited actors in the film include Enzo Santaniello (Timmy), Simonetta Santaniello (Maureen), and Stefano Imparato (Patrick) as the McBain children; Al Mulock as the third station gunman Knuckles; Conrado San Martín as Vecino, Marco Zuanelli as Wobbles, and Claudio Mancini as Harmonica's brother.

United Artists (which had produced the Dollars Trilogy) offered him the opportunity to make a film starring Charlton Heston, Kirk Douglas and Rock Hudson, but Leone refused.

[15]: 30–31 Beginning with The Good, the Bad and the Ugly, which originally ran for three hours, Leone's films had usually been cut (often quite considerably) for box-office release.

The tone of the film is consistent with the arid semidesert in which the story unfolds, and imbues it with a feeling of realism that contrasts with the elaborately choreographed gunplay.

After the screening and a meeting with Leone, Fonda called his friend Eli Wallach, who had co-starred in The Good, the Bad and the Ugly.

[14] French actor-filmmaker Robert Hossein was set to play a supporting role as a member of Frank's gang, and is listed in the cast by some sources (including the AFI Catalog of Feature Films[23]).

[24] Following the film's completion, Once Upon a Time in the West was dubbed into several languages, including Italian, French, German, Spanish, and English.

[25] For the English dub, the voices of many of the American cast, including Fonda, Bronson, Robards, Wynn, Wolff, and Lionel Stander, were used.

The film features leitmotifs that relate to each of the main characters (with their own theme music), as well as to the spirit of the American West.

[27] Especially compelling are the wordless vocals by Italian singer Edda Dell'Orso during the theme music for Jill McBain.

Leone had Morricone compose the score before shooting started and played the music in the background for the actors on set.

[27] Except for about a minute of the "Judgment" motif, before Harmonica kills the three outlaws, no soundtrack music is played until the end of the second scene, when Fonda makes his first entry.

[29][30] It sparked a brief fashion trend for duster coats, which took such proportions that Parisian department stores such as Au Printemps had to affix signs on escalators warning patrons to keep their "maxis", as they were called, clear from the edges of moving steps to prevent jamming.

In Italy, a 171-minute director's cut features a yellow tint filter, and several scenes were augmented with additional material.

[nb 1] This release is the color 2.35:1 aspect ratio version in anamorphic widescreen, closed captioned, and Dolby.

While viewing Cardinale as a good casting choice, he said she lacked the "blood-and-thunder abandon" of her performance in Cartouche (1962), blaming Leone for directing her "too passively".

[40] Directors such as Martin Scorsese, George Lucas, Quentin Tarantino,[41] and Vince Gilligan[42] have cited the film as an influence on their work.

The critical consensus reads: "A landmark Sergio Leone spaghetti Western masterpiece featuring a classic Morricone score".

[44] Metacritic gives the film a weighted average score of 82 out of 100 based on reviews from 9 critics, indicating "universal acclaim".

The film is recognized by American Film Institute in these lists: Leone's intent was to take the stock conventions of the American Westerns of John Ford, Howard Hawks, and others, and rework them in an ironic fashion, essentially reversing their intended meaning in their original sources to create a darker connotation.