Humphrey Bogart visited the set as he began to film La mano sinistra di Dio (1955). Lauren Bacall later recalled that John Wayne was the first to send flowers after Bogart became ill with cancer in 1956, even though he hardly knew Bogart.
In an interview Lauren Bacall said that she took the role because Robert Mitchum was to be the male lead. After John Wayne took the role following Mitchum's departure, she expected to clash with him since she was a left-wing Democrat and he was a right-wing conservative Republican. She said that he was warm and friendly and they did not discuss politics. She later starred with him again in his last movie Il pistolero (1976).
Lauren Bacall said of this film, "That was supposed to be [Robert Mitchum], but he got into some brouhaha--probably had a few too many. [William A. Wellman was great; Wild Bill, a fascinating man! Not a good movie, but I liked working with Duke [John Wayne]. We didn't agree politically, but we got along well and had a sort of chemistry."
Robert Mitchum was originally cast as Capt. Wilder. He was fired from the film after an altercation in which he shoved the film's transportation manager into San Francisco Bay. Director William A. Wellman complained to John Wayne--whose company, Batjac Productions, was producing the film--that Mitchum "was on dope, always walking about six inches off the ground." Wellman said either he or Mitchum had to go. Gregory Peck subsequently turned down the role because he found it offensive and Humphrey Bogart wanted a $500,000 salary, which would have put the film over budget. Without a major male star involved, Warner Bros. contacted Wayne, threatening to pull out of their distribution deal for the film unless he took the role himself. To keep his new production company afloat, Wayne agreed to replace Mitchum.
John Wayne temporarily directed this film while director William A. Wellman suffered from influenza.