The studio bought the rights to the James brothers, but changed the facts for entertainment. Although Frank surrendered and stood trial for several robberies without being convicted, he never sought revenge on the Ford brothers. Charlie committed suicide in 1884 and Robert was murdered in Colorado in 1892.
The original treatment had Frank romantically interested in the reporter played by Gene Tierney, but the studio became fearful of a possible lawsuit by Frank's widow and/or son, so it was eliminated from the script.
In Jess il bandito (1939) and this sequel, John Carradine plays the historical figure Bob Ford, the resentful member of the James-Younger gang, who shot and killed Jesse James. The movie I cavalieri dalle lunghe ombre (1980) features Carradine's three sons David, Keith and Robert in the roles of the gang's Younger brothers.
As with their previous collaboration, You Only Live Once (1937), Henry Fonda loathed working with Fritz Lang due to his bullying conduct.