The Sunshine star will play John Bianchi, the son of mobster Bruno Bianchi, according to TV Line.
When Bruno's untimely demise is covered up, John will confront Nick Dalton (Eddie Cibrian) for information on his father's whereabouts.
Garity previously starred in 2002 film Barbershop and its 2004 sequel, and also appeared in 2001's Bandits and 2004's After the Sunset.
The actor's past television credits include guest roles on House and Hawaii Five-0. He will make his Playboy Club debut in the show's second episode.
Hugh Hefner recently revealed that he will only have a minimal role as a character in The Playboy Club, while the Parents' Television Council has urged NBC affiliates not to air the drama despite admitting that it has not seen a full episode.
The Playboy Club premieres on Monday, September 19 on NBC.
> Playmate Claire Sinclair auditions for The Playboy Club
Watch a clip from The Playboy Club below: