In this movie, Valdez appears as a part-time shotgun rider on the Hatch & Hodges stagecoach. Elmore Leonard, who wrote the novel that this movie is based on, used the same stagecoach service in other of his novels, like "Hombre" and "Last Stand at Saber River".
When MGM producer Ira Steiner took Elmore Leonard's novel to Burt Lancaster, the actor agreed to co-produce and co-star as Tanner, with ] Marlon Brando as Valdez, David Rayfiel as writer and Sydney Pollack directing. After the picture was postponed to allow Lancaster to do Airport (1970), the actor decided he wanted to play the title role and engaged Roland Kibbee to rewrite the role for him. According to Lancaster's biographer Gary Fishgall, none of Rayfiel's writing was used although he received co-credit.
Novice director Edwin Sherin, who had guided "The Great White Hope" to stage success, was Burt Lancaster's surprise choice to direct this film. Ironically the film version of "The Great White Hope" (The Great White Hope (1970)), directed by Martin Ritt, was filmed in Spain at the same time "Valdez" was filming.