Ace Harlem was police detective from an unnamed large city whom had an incredible sense for honor and justice and had, from a young age on, a profound anger against criminals and crime in general. This got him great respect in the Afro-American community amongst others in his home city.
Ace Harlem was created by the comic book company All-Negro Comics, which was the first publisher that consisted solely of Afro-American creators and the heroes. The comics book were also all Afro-American or African heroes. Ace Harlem was not a superhero, but is one (if not the first) heroic black comic character.
Unfortunately, only 1 issue of the comic-series was printed, even though issue 1 announced a second issue with another adventure of Ace Harlem.