Mercedes Alicia McNab, now in her mid-twenties, is an only child. She has been acting professionally since she was 10, and her best known film role is probably as the girl scout in the Addams Family and its sequel. She has also appeared in the films Savage Land and Escape from Atlantis, among others. She has been on TV in shows such as Harry and the Hendersons, USA High, and Touched by an Angel. Mercedes is currently living in Los Angeles with her parents.
In 1997, Mercedes got a role as Harmony on the television show, Buffy the Vampire Slayer. She would continue to play this role in the shows first five seasons, then she moved to Buffy's sister show, Angel for one episode in its second season. In mid 2004, Mercedes, after 8 years of working in the "BuffyVerse," became a regular character on Angel in the series fifth season.