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 Wellman complained to Wayne that the star "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 of Capt. Wilder, 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 producer John Wayne, threatening to pull out of their distribution deal for the film unless he took the role himself. To keep his new production company Batjac afloat, Wayne agreed to play Capt. Wilder.
Average Shot Length = ~6.2 seconds. Median Shot Length = ~5.6 seconds. Both of these figures are fast for an early CinemaScope film, and much faster than William A. Wellman's first CinemaScope film, The High and the Mighty.
John Wayne appeared in an episode of I Love Lucy to promote this film. In a scene when Lucy is hiding in Wayne's trailer on set, a worker brings in the large poster for "Blood Alley" for his approval just before he is about to receive a massage. As Lucy tries to sneak away, he hears her and makes her give the massage without ever seeing her.
In an interview Lauren Bacall said that she took the role when Robert Mitchum was to be the male lead. When John Wayne took the role after Mitchum was fired she expected to clash with him since she was a left-wing Liberal and he was a right-wing Conservative. She said that he was warm and friendly and they did not discuss politics. She later starred with him again in his last movie 'The Shootist' (1976).