According to Sergio Corbucci, Marcello Mastroianni gave him the idea of a mute gunfighter when the actor told him that he had always wanted to do a Western, but unfortunately didn't speak English. When Corbucci first met Jean-Louis Trintignant, he learned that he didn't speak English either. Because he had a fascination with characters with a crippling weakness, Corbucci decided that this was the moment to turn the taciturn Spaghetti Western hero into a mute.
Silence's distinctive rapid-firing pistol is the 7.63mm Mauser C96, nicknamed the "Broomhandle" for its distinctive wooden grip. The pistol was first produced in 1896, two years before the events of the film.
The film's Italian trailer includes an appraisal of the film attributed to 20th Century Fox (the film's distributor in Italy and other territories) co-founder Darryl F. Zanuck, which reads: ''Il migliore western all'italiana degli ultimi tempi'' (The best Spaghetti Western of recent times). In reality, Zanuck was offended by the film's grim ending, and refused to release it in the United States.
In publicity photos, Loco is shown holding a "WANTED" poster of an outlaw named Manuel Vasquez, a character who is not seen in the film. The poster is, in fact, a leftover prop from 10,000 Dollars for a Massacre (1967), in which Vasquez is a character played by Claudio Camaso. In The Great Silence (1968) itself, Vasquez's face on the poster is kept out of view.
(English-language version) Loco's statement to Miguel's mother that they kill bandits for their "bread and butter" contrasts with Pollicut's sarcastic statement that the bandits have to be "fought with bread and butter" at the advice of Sheriff Burnett.