Gene Hackman as Harry Caul

John Cazale as Stan

Allen Garfield as William P. 'Bernie' Moran

Frederic Forrest as Mark

Cindy Williams as Ann

Michael Higgins as Paul

Elizabeth MacRae as Meredith

Teri Garr as Amy Fredericks

Harrison Ford as Martin Stett

Mark Wheeler as Receptionist

Robert Shields as The Mime

Phoebe Alexander as Lurleen

Ramon Bieri as Man at Party (uncredited)

Gian-Carlo Coppola as Boy in Church (uncredited)

Robert Duvall as The Director (uncredited)

Richard Hackman as Confessional Priest / Security Guard (uncredited)

Billy Dee Williams as Man in Yellow Hat (uncredited)