Father Edward Flanagan, who died almost ten years after this movie was released, was the first person ever to live to see somebody win an Oscar for portraying him.
When shooting began on the movie, Mickey Rooney repeatedly tried to steal scenes by fumbling with a handkerchief, pulling faces and other bits of business. This so annoyed Spencer Tracy that he threatened to have Rooney thrown off the movie unless he behaved.
The day after Spencer Tracy won the Best Actor Oscar for his performance in this film, an MGM publicist released a statement - without consulting Tracy first - that the actor would donate his Oscar to the real Boys Town in Nebraska. Tracy agreed to make the donation if the Academy would send him a replacement Oscar. When the replacement arrived, the engraving on the award read: "Best Actor - Dick Tracy."
Father Flanagan was paid $5000 for the movie rights to his book; the movie made a profit of $2 million.
Boys Town is a real city in Douglas County, Nebraska. It has a boy mayor, a post office and police department (staffed by adults/sworn officers). The 2010 population of Boys Town was 745. The highest population for Boys Town was 997 in the 1960 census.