For the location shoot in the Northeast for A Letter to Three Wives, weather problems affected the production schedule, reducing the amount of footage filmed there. Although scenes were shot in Manhopac, Hook Mount and Cold Spring, NY, a scene scheduled for Stamford, CT, had to be shot in Beverly Hills, CA, instead.

To get the proper look of disgust from Linda Darnell when she sees Addie's picture on her beau's piano, director Joseph L. Mankiewicz substituted a picture of colleague Otto Preminger dressed as a Nazi. Preminger had directed her in Fallen Angel (1945) and Forever Amber (1947) and was notorious for his abuse of actors.

When Ann Sothern's look of joyful surprise on finding her husband hadn't run off with Addie wasn't strong enough, Mankiewicz had Kirk Douglas jump up from behind the set's sofa (out of camera range) in only his underwear.

Studio head Darryl F. Zanuck was so impressed with A Letter to Three Wives, he arranged to open it at the Radio City Music Hall in New York City instead of 20th Century-Fox's flagship theatre there, the Roxy. That was one reason the picture, which had been finished in August 1948, was not released until January 1949.

Before filming a scene in which Kirk Douglas had to wake up, director Joseph L. Mankiewicz asked him to make the scene as realistic as possible by actually trying to fall asleep. Douglas managed to do so, but as soon as he drifted off, Mankiewicz dismissed the company for lunch, and they all slipped out. The actor woke up to an empty set.

20th Century-Fox promoted A Letter to Three Wives with the tagline, "All of them wondered which one of them wandered."

by Frank Miller