Bing Crosby almost turned down the film because he thought he was too old for his character and wouldn't be able to play it.
For his big drunk scene, Bing Crosby had his sons Dennis Crosby and Phillip Crosby keep him up all night so that he'd look suitably worn out. Ironically, the day this scene was shot was the day that Crosby's mother showed up to watch some filming. She was so horrified by his appearance that she stormed out.
Edith Head who was in charge of Grace Kelly's wardrobe said, "I had to take one of the most beautiful woman in the world and make her look plain and drab." Head used brown wool clothes, cardigan sweaters, and low-heeled Capezio shoes to make Kelly appear dowdy.
Grace Kelly won her only Oscar for her role in this movie beating out Judy Garland, the sentimental favorite, in reportedly the closest Best Actress race in Academy history besides the Barbra Streisand and Katharine Hepburn tie for 1968. Hedda Hopper reported that 6 votes was all that separated Grace Kelly and Judy Garland.
Paramount borrowed Grace Kelly from MGM for the lead role. MGM initially refused to loan her until Kelly threatened to quit acting altogether if they didn't let her play the role.