According to co-star John Saxon, Marlon Brando's relationship with director Sidney J. Furie got to the point where Brando, when getting ready to do a close-up, would be reading a book. He would only lower the book when Furie yelled "Action." When he yelled "Cut," Brando would raise the book again. According to Peter Manso's book on Brando, however, Brando and Furie met years later. Brando was quoted to have said, "I thought you were a no-good double-crosser, and I didn't know if I could trust you, but I saw the film and you have the great sense of the best visual directors. Let's do another movie together." Furie, according to the book, replied, "Never!" Furie, for his part, claims that they only came to blows once on the entire shoot of The Appaloosa (1966).

According to Bob Thomas' 1973 biography "Marlon: Portrait of the Artist as a Rebel," producer Alan Miller, appalled at his star's lack of interest in the film and his lackluster performance, penned a bit of doggerel about Marlon Brando, whose character is called "Mateo" by his Mexican friend in the film, "Mateo, his heart/It bleeds for the mass,/But the people he works with/He kicks in the ass."

Sidney Furie, the director, had many problems on the set because of his way, his method of filming, the weird angles he asked of the camera operator, an old timer in the movie business since Gone With the Wind. Marlon Brando also told Furie that he was a lousy director.

Claudia Cardinale was originally sought for the Anjanette Comer part.