A versatile character player with a distinctive high, soft, slightly hoarse voice, Kirby is perhaps best remembered as the young Clemenza in Francis Ford Coppola's "The Godfather, Part II" (1974) and the humorless Lt. Hauk in Barry Levinson's "Good Morning, Vietnam" (1987). The son of actor Bruce Kirby, he has been variously billed as Bruce Kirby Jr and B Kirby in his career. Although when younger he was often cast as dweebish characters (as in the sexually-repressed youth in his first film 1973's Harrad Experiment"), as Kirby has matured, he began to play more earthy and street-smart buddies