Granite-jawed, angular-faced American character actor of films and television who specialized in desperate men on both sides of the law. Found a perfect niche in science-fiction, given particularly meaty roles in the original The Twilight Zone (1959), The Outer Limits (1963) and The Invaders (1967).
He was the son of Madeline (De Luca), and Tomaso Guadagno of Rhode Island. He was of Italian descent.
Played both Detective Delgetti in the 1968 crime thriller Bullitt and crazed criminal Anthony Delgetti 17 years later in the TV series Remington Steele.