Barry Fitzgerald was nominated by the Academy for both Best Actor and Best Supporting Actor awards for the same performance, the only time this has ever happened. He won the Oscar in the supporting category but lost in the lead category to co-star Bing Crosby (This is no longer possible under Academy guidelines.) Due to wartime metal shortages, Fitzgerald received a plaster Oscar (instead of a gold one) for his performance. A few weeks after he won, he broke the head off his plaster Oscar while practicing his golf swing.
Although Barry Fitzgerald played a Catholic priest in this film--and several others--he was in real life not a Catholic but a Protestant. Several times during this film when he is "crossing" himself he does it wrong, going from right to left instead of from left to right.
The film was actually written after its "sequel" The Bells of St. Mary's (1945); in order to borrow Bing Crosby from Paramount for that film, RKO had to allow Leo McCarey to write and direct "Going My Way", based on the same character. Oddly, however, "Going My Way" was released first.
Singer Andy Williams debuted as one of the singing boys surrounding Bing Crosby during the song "Swinging On A Star". Williams and his three other brothers were performing as the Williams Brothers and were all cast in the scene.
Risë Stevens' character of Genevieve Linden is playing the title role in "Carmen" at the Metropolitan Opera in 1944. Ms. Stevens would not make her debut in this role at the Metropolitan until December 28, 1945.
Filmed in St. Monica Catholic Church near the beach in Santa Monica, California. Leo McCarey based the Barry Fitzgerald character in part on the church's real (irascible) pastor, Msgnr. Nicholas Conneally.