NOTE: As mentioned elsewhere, DC comics has had many characters that went by the name "Manhunter". The first costumed Manhunter from DC originally appeared in Adventure Comics #73 (April 1942), but a month before that, rival publisher Quality Comics premiered their own Manhunter in Police Comics #8 (March 1942):
Eventually, however, Quality Comics gave up publishing comic books in the 1950s, with DC Comics taking over many of their former properties.
The (formerly) Quality Comics version of "Manhunter" did eventually meet up with the DC Comics character of the same name. I believe that first run-in was in the pages of All-Star Squadron #31 (March 1984):
And from the pages of Who's Who: The Definitive Directory of the DC Universe Vol. XIV (April 1986):
NOTE: This thread is specifically for the Donald / Dan Richards version of Manhunter. If people wish to discuss other versions, please look for (or create yourself if they don't already exist) separate threads regarding those other versions.