Both Fisk and his partner Ned Stokes (called Nick Boyd in the movie) were married but competed for the affections of showgirl Josie Mansfield. In real life she was a world-wise dark-haired, full-figured woman who bore little resemblance to the innocent, apple-cheeked blonde sincerity of Francis Farmer. Stokes and Mansfield blackmailed Fisk, and Stokes shot Fisk to death in 1872. Although the dying Fisk named Stokes as his murderer, he only served four years of a six year term for manslaughter.
The film lost $530,000 ($10.85M in 2022) at the box office, RKO's biggest failure in 1937.
Unlike the events in the film, Jim Fisk was shot and killed in a fight over a woman. Josie Mansfield was only one of his romantic interests.
No mention is made of Jay Gould, the notorious robber baron, who conspired with Fisk to corner the gold market in The Panic 1869, three years before Fisk's death.
The Bowery Boys employed by Vanderbilt against Fisk have no relation to the long-running film series of the same name but were a real-life Manhattan gang later portrayed in more detail in Martin Scorsese's Gangs of New York (2002).