Director Sam Peckinpah tried to get this movie produced for years, but unfortunately he died before he had the chance.
Having spent a week volunteering for Mother Teresa's children's sanctuary, Penélope Cruz donated her entire salary for this film to the charity.
While making Major Dundee (1965), Sam Peckinpah and Charlton Heston discussed making this. Even after the friction on that shoot, they were still looking at making it in May 1965.
Same author who wrote Hi-lo, Max Evans, wrote The Rounders. It was made into a movie in 1965 and stared Glen Ford and Henry Fonda. Sam Elliots character Jim Ed Love, is played by Chill Wills in The Rounders. Glen Ford plays Ben Jones and Henry Fonda plays Marion "Howdy" Lewis.