"Theater Guild on the Air" broadcast a 60 minute radio adaptation of the movie on December 8, 1946 with Sam Levene reprising his film role.

Lee J. Cobb, playing 20-year-old William Holden's middle-aged father, was actually only 27.

William Holden was considered not to be up to the role in the film, however Barbara Stanwyck urged producers to keep him in the picture, and succeeded. In 1978, at the The 50th Annual Academy Awards, before starting the presentation of the sound award, Holden publicly thanked Stanwyck for what she did.

William Holden was knocked unconscious one day while boxing on the set with James 'Cannonball' Green. He thought the footage of the knockout would be spectacular but director Rouben Mamoulian said it couldn't be used because it didn't look real. Holden recalled that, real or not, his head ached for a week.

William Holden was so grateful to Barbara Stanwyck for her insistence on casting him in Golden Boy, his first big role, that he reportedly sent her flowers every year on the anniversary of the first day of the filming.

Almost 5000 actors had been considered for the part of Joe Bonaparte--among them a 17-year-old Dale Robertson--and more than 80 had been given screen tests. The odds of getting the highly desirable part were against the unknown William Holden, but Barbara Stanwyck and director Rouben Mamoulian lobbied on his behalf.

Columbia could not use Richard Carlson, its first choice for the title role, because Carlson was appearing in a Broadway play, "Stars in Your Eyes". The studio then cast William Holden in the part.

The play originally opened in New York on 4 November 1937 and had 250 performances. Luther Adler played Joe Bonaparte, Frances Farmer played Lorna Moon and Roman Bohnen played Tom Moody. Lee J. Cobb was also in the play as Mr. Carp.

To convincingly portray a boxer who was also a violinist, William Holden took boxing and violin lessons all day every day for a week before production began. He continued to prepare during the 11 weeks of filming by boxing two hours daily and practicing the violin for 1-1/2 hours each night so his fingering of the instrument would be convincing.

When Clifford Odets wrote his play, he had John Garfield in mind for the Joe Bonaparte part, but the Group Theatre company chose Luther Adler instead. Shortly afterward, Garfield left the Group Theater and was Hollywood bound.