John Huston wanted a then almost-unknown Marilyn Monroe for a part in this movie. He made it about Cuban rebels at the time Monroe had a contract with Columbia. But producer Sam Spiegel didn't want to spend money for a screen test of Monroe.
One of the writers, Peter Viertel, wrote a chapter in his book Dangerous Friends about how he and John Huston wrote the screenplay for We Were Strangers, including two weeks in Cuba with Ernest Hemingway. According to Viertel, Hemingway suggested ending the film as it occurred in reality: with the death of the revolutionaries. Instead, an alternative ending was supplied by Ben Hecht.
At the time depicted in this film, the Cuban peso was at par with the U.S. dollar. The 2,000 peso check would be the equivalent of about $40,000 in 2021.
John Huston says in his autobiography that Jennifer Jones needed him to tell her where to walk, where to sit, how to behave in any situation.
A magazine review of Robert Sylvester's original book had suggested that it might make an ideal subject for a John Huston movie, and this was what led Huston to make it - a bad idea, he later admitted. He never liked the film much. It was his first collaboration with producer Sam Spiegel, with whom he had a very edgy friendship.