After appearing as Young Peter Clemenza in The Godfather: Part II and as Tommy Pischedda in This Is Spinal Tap, this New York-born actor played Jess in When Harry Met Sally and Nicky Santora in Donnie Brasco. In addition, he was nominated for an American Comedy Award for his role as Ed Furillo in City Slickers.
After studying at New York City's Power Memorial Academy, he made his screen debut in the 1971 feature The Young Graduates.
His television credits include episodes of M*A*S*H* and Room 222.
His father, Bruce Kirby, had a successful career as a television and film character actor, and his brother, John Kirby, became a notable acting teacher.
In the early 1990s, he replaced Kevin Spacey in the Broadway production of Lost in Yonkers.