Trivia: The opening credits list a copyright date of 1947, but distributor RKO rushed IAWL into theaters December 20 1946, to replace 'Sinbad the Sailor' whose Technicolor prints were not ready. It went into general release January 1947. The rush probably cost Capra and his partners their indie studio Liberty Films, whose first production opened in a record blizzard back east and failed to make back its money; it also wound up losing out at the Oscars against a powerful postwar drama 'The Best Years of Our Lives' rather than facing a much weaker Oscar field in 1947. Then again, confusion over its copyright date seems to have allowed it to slip into public domain for about 20 years from 1973, leading to its constant (cost-free) play at Christmas time, cementing its reputation as America's favorite holiday movie.
Trivia: Melinda Dillon was given the wrong script on purpose when they filmed the Chinese restaurant scene. She had no idea that when they brought the duck out it would have its head still attached. All of her reactions, including when she first sees the duck and when the server cuts the head off, were completely genuine.
Trivia: When the real Santa and the fake Santa are fighting on the sleigh when the fake Santa is heading out to deliver coal to all the children, the fake Santa says something like 'You are a strange little man.' Buzz Lightyear (voiced by Tim Allen) in the movie Toy Story said the same thing to Woody.
Trivia: When Bob is doing his audition, he is wearing a red top with black shorts. On Bob's left shoulder, the name Ben is written on the top. Ben is the actor's real name.
Trivia: When Billy's mom takes the picture of Gizmo at the beginning, Gizmo becomes frightened and runs over to Mr. Peltzer. When the scene is slowed, you can see the puppeteer's hand underneath while operating the Gizmo doll. Not a mistake as needs slo-mo, but worth a look. (00:19:10)