William Holden almost turned down the film because he thought he was too old at 37 to play Hal Carter. Audiences agreed that he was much too old to play a character in his twenties.
During the dramatic sunset scene with Rosalind Russell and Arthur O'Connell, when Rosemary, the schoolteacher looked out at the deep red sky and remarked that sometimes the day puts up a fight against being night, what they really were looking at was the leading edge of a very large approaching thunderstorm. It contained a tornado which hit a nearby town. A few minutes after shooting the scene, the movie company themselves had to take cover.
The last aerial shot of the bus and the train was filmed by Haskell Wexler, who was James Wong Howe's assistant at the time. The cameraman simply leaned out the open door of the helicopter for several minutes with no safety harness, with his right leg wrapped around a strut, following the bus overtaking the train below.
While selecting locals to play extras in the film, Joshua Logan said, "There's a girl with a typical Kansas face." The woman was hired for atmosphere but confessed, "I'm from Brooklyn. I'm just here visiting my grandmother."
For a scene in which she had to cry, Kim Novak asked director Joshua Logan to pinch her black-and-blue off-screen, telling him, "I can only cry when I'm hurt."