No. The boxer named Jack Jenkins in the 1989 film, Harlem Nights, is fictional and not based on a real person.
The actor who played him, Stan Shaw, also played a professional fighter in Snake Eyes (1998) and Tough Enough (1983). He also appeared in Rocky (1976) and portrayed boxing legend Joe Louis in the TV movie The Court-Martial of Jackie Robinson.
Harlem Nights may have forever scarred actor Stan Shaw for playing the stuttering champ Jack Jenkins. Every time we see him, we can't help but to expect him to be stuttering.
Stan Shaw started acting in the Chicago production of the Broadway musical Hair as well as the Broadway production of The Me Nobody Knows. His last Broadway show, Via Galactica, was directed by Sir Peter Hall.
Know more about Stan Shaw from his IMDb page.
For the latest updates, follow him @StanShaw1 on Twitter.