According to Peter Bogdanovich in "Pieces of Time" Richard Widmark stated he had more fun on this film than any other. "I'm a little deaf in this ear . . . and [John Ford]'s a little deaf in the other, and [James Stewart's hard of hearing in both! . . . So all through the picture, all three of us were goin', 'What? What? What?'"
Richard Widmark was initially reluctant to make the film, since he felt he was 15 years too old for the young lieutenant he played.
This was the last film in which James Stewart wore his familiar cowboy hat. Up to this point he had worn it in all his westerns since Winchester 73 (1950). This was Stewart's first film with John Ford and Ford didn't want him to wear it, as he thought it was the worst-looking cowboy hat he had ever seen. Ford quipped, "Great, now I have actors with hat approval." As Stewart said in the documentary, A Wonderful Life (1989), Ford relented but got back at Stewart in their next western, Un tiro en la noche (1962), when he didn't let Stewart wear a hat at all.
James Stewart had been warned about John Ford's behavior by such longtime friends as John Wayne and Henry Fonda. Stewart came to learn Ford liked to keep his actors in the dark about the direction of the picture and suspicious of each other. In Andrew Sinclair's biography "John Ford", Stewart revealed that Ford's "direction took the form of asides. Sometimes he'd put his hand across his mouth so that others couldn't hear what he was saying to you. On Two Rode Together, he told me to watch out for Dick Widmark because he was a good actor and that he would start stealing if I didn't watch him. Later, I learned he'd told Dick the same thing about me. He liked things to be tense."
The dialog in the scene where James Stewart and Richard Widmark sit by the river was largely improvised.