When Twentieth Century-Fox bought the rights to the Francis Gwaltney novel "The Day the Century Ended", it hired The Twilight Zone (1959) television-playwright and Philippines war veteran Rod Serling to write the script. During World War II, Serling was a paratrooper in the 511th Parachute Infantry Regiment of the 11th Airborne Division. However, his draft script was deemed too long and rejected. Other writers were then assigned script duties. He does not receive a writer's credit, so it's not known how much of his work wound up in the final script. He once told of his involvement on this movie, "My first screen job was at Fox on a war flick called 'Between Heaven and Hell'. I turned in a script that would have run for nine hours on the screen. As I recall, it was over 500 pages. I didn't know what the hell I was doing. They just said ''Here's 1500 bucks a week--write!" So I wrote. They eventually took the thing away from me and handed it over to six other writers, but I lay claim to the fact that my version had some wonderful moments in it. In nine hours of script, by God, there HAVE to be a couple of wonderful moments!"
Filmed mostly in Southern California at the Twentieth Century-Fox ranch in the Santa Monica Mountains. However, the beach landing was filmed on the island of Oahu in Hawaii.
Hugo Friedhofer's music score for this film uses elements as a motif from "Dies irae" ("Day of Wrath"), a 13th-century Latin hymn.
The Fox movie ranch, between Malibu and Calabasas, was also the distant location where How Green Was My Valley, Planet of the Apes, and M*A*S*H were filmed. Mr. Blandings' house is still there, inhabited by state Park Rangers. The entrance is at Malibu Canyon Road and Mulholland Hwy. There are California Live Oaks all over those hills, with potted palms brought out from the Fox lot where portable foliage was kept.