The film has two lines of "secret dialog" - spoken quietly through a door. (They can be heard when amplifying the volume, and are also explicitly depicted in the closed-captioning.) The lines occur at the end of the scene set in Bailey's private office with Bailey and his son George, and Potter and his goon present. After George raves to Potter that "you can't say that about my father", he is ushered out of the room by his father, then George is shown standing outside the office door. At that moment, George overhears the following two lines of dialog through the glass pane of the door behind him: POTTER: What's the answer? BAILEY: Potter, you just humiliated me in front of my son.
The gym floor that opens up to reveal a swimming pool was real and was located at Beverly Hills High School in Los Angeles.
The instant that George says "God" on the bridge, it starts snowing, showing that he is back in the real world.
The movie was originally slated for 1947 release, but when Technicolor was unable to deliver prints in time for RKO's Christmastime 1946 release of Sinbad the Sailor, Frank Capra's film was rushed into theaters. The titles were not reshot, and thus bear a 1947 copyright.
The name of Bedford Falls was combined from Bedford Hills, in Westchester County, New York, and Seneca Falls, a small town midway between Rochester and Syracuse. The town of Elmira, mentioned by the bank examiner, is a real town in New York, not that far from the actual Seneca Falls.
The scene on the bridge where Clarence saves George was filmed on a back lot on a day where the temperature was 90 degrees Fahrenheit. This is why James Stewart is visibly sweating in a few scenes.
The set for Bedford Falls was constructed in two months and was one of the longest sets that had ever been made for an American movie. It covered four acres of the RKO's Encino Ranch. It included 75 stores and buildings, main street, factory district and a large residential and slum area. The Main Street was 300 yards long, three whole city blocks!
This film is one of five times Beulah Bondi portrayed James Stewart's mother, The others are: Mr. Smith Goes to Washington, Of Human Hearts and Vivacious Lady, and once on his television series, The Jimmy Stewart Show.
This was the first and last time that Frank Capra produced, financed, directed and co-wrote one of his films.
Two of Sesame Street's Muppets, Bert and Ernie, share their names with the film's cop and cab driver, respectively, but it's believed to be just a coincidence. While Karolyn Grimes, who played Zuzu, claimed that the two Muppets were named after the characters because the movie was Jim Henson's favorite, according to longtime Muppets head writer Jerry Juhl in an interview with The San Francisco Chronicle, Ernie and Bert were not named after the movie's characters. Juhl said, "I was not present at the naming, but I was always positive the rumor was incorrect. Despite his many talents, Jim Henson had no memory for details like this. He knew the movie, of course, but would not have remembered the cop and the cabdriver. I was not able to confirm this with Jim before he died, but shortly thereafter I spoke to Jon Stone, Sesame Street's first producer and head writer and a man largely responsible for the show's format. He assured me that Ernie and Bert were named one day when he and Jim were studying the prototype puppets. They decided that one of them looked like an Ernie, and the other one looked like a Bert. The movie character names are purely coincidental."
Voted the #1 inspirational film of all time in AFI's "100 Years, 100 Cheers" (June 14th, 2006)
When composer Dimitri Tiomkin's original score for the finale (featuring "Ode To Joy") was eliminated, tracks of Alfred Newman's score from The Hunchback of Notre Dame were used instead, most notably the chorus singing "Hallelujah".
When Officer Bert shoots at George, the "s", the "v" and the "i" in the electric "Pottersville" sign far away in the distance, go out.
While filming the scene where George prays in the bar, James Stewart has said that he was so overcome that he began to sob right then and there. Later, Frank Capra reframed the shot so it looked like a much closer shot than was actually filmed because he wanted to catch that expression on Stewart's face.
Olivia De Havilland was offered the role of Mary Hatch Bailey in It's a Wonderful Life (1946) after Jean Arthur turned it down, but she also turned down the part. Donna Reed was cast instead and it went on to be one of her most famous performances.