Howard Hawks shot the beginning of the cattle drive in close-ups of each of the principal cowhands because he felt tight shots would be needed to help the audience keep all the characters straight in their minds. To that end, he also gave them all different kinds of hats, including a derby. Montgomery Clift used Hawks' own hat, which was given to him by Gary Cooper. Cooper had imparted a weather-beaten look to the hat by watering it every night. "Spiders built nests in it," Hawks said. "It looked great."
Montgomery Clift was nervous about standing up to John Wayne but gained confidence when Howard Hawks told him to play his scenes like David against Goliath. He also urged the young actor to underplay in his scenes with Wayne, particularly the scene in which his character challenges Dunson for the first time. Wayne was also not sure Clift could be convincing as a rugged cowboy, but after that first confrontation scene he told Hawks his doubts were gone and "he's going to be okay."
Montgomery Clift had learned to ride horses while at military prep school, but it was a different kind of riding than he was required to do in this role. He asked experienced Western actor Noah Beery Jr.. for help and worked hard to become convincing on screen. Beery later said, "The thing he enjoyed most was becoming a hell of a good cowboy and horseman." Howard Hawks always had high praise for how hard Clift worked on the picture.
After seeing John Wayne's performance in the film, directed by rival director Howard Hawks, John Ford was quoted as saying, "I never knew the big son of a bitch could act." This led to Ford casting Wayne in more complex, multi-layered, and dramatic roles in films like She Wore a Yellow Ribbon (1949), The Searchers (1956), and The Man Who Shot Liberty Valance (1962). However, it is worth noting that the only source for Ford's quote was Howard Hawks himself, who always liked to make himself look good in relation to other famous directors.