Baltz is best known for his role as Marvin Nash, an LAPD police officer in the famous torture scene of the 1992 Quentin Tarantino film Reservoir Dogs. Kirk also starred in another film written by Tarantino, 1994's Natural Born Killers, as "Roger". He appeared in the 1997 action film Face/Off and in the 1990 film Dances with Wolves.
Kirk has appeared in many made-for-TV movies and he starred in the 1999 miniseries To Serve and Protect. He starred in the short lived 1992 TV series Human Target, and played sinister stalker Steve Roth in The Marla Hanson Story (1991).
He has made guest appearances on numerous TV shows including Will and Grace, NYPD Blue, Seven Days, The Shield, 24, and Without a Trace. Kirk has also been the only actor to portray Batman villain Clayface in live-action, in the short-lived series Birds of Prey.
Kirk Baltz currently operates a successful acting school and coaches actors of all levels in Los Angeles, California.