The mongrelman appeared in second edition in the Monstrous Compendium Volume Two (1989), and Monstrous Manual (1993). The mongrelman is presented as a playable character race in The Complete Book of Humanoids (1993), and is later presented as a playable character race again in Player's Option: Skills & Powers (1995). The mongrelman is further detailed in Dragon #242 (December 1997), which also introduced the infiltrator mongrelman.
While in older editions of Dungeons & Dragons mongrelfolk were defined as deformed outcasts, recent sourcebooks (Races of Destiny, Wizards of the Coast, 2006) gave them the special ability to appear as members of any other race. As such they mix into humanoid society by impersonation rather than being outcast.