Robert Redford as John Dortmunder

George Segal as Andrew Kelp

Ron Leibman as Stanley Murch

Paul Sand as Alan Greenburg

Moses Gunn as Dr. Amusa

William Redfield as Lt. Hoover

Topo Swope as "Sis" Clara Kelp

Charlotte Rae as Ma Murch

Graham Jarvis as Frank, the Prison Warden

Christopher Guest as Policeman

Zero Mostel as Abe Greenberg

Harry Bellaver as Rollo the Bartender

Seth Allen as Happy Hippie

Robert Levine as Cop At Police Station

Ed Bernard as Policeman

Lee Wallace as Dr. Strauss

Robert Weil as Albert

Lynne Gordon as Miasmo

Grania O'Malley as Bird Lady

Fred Cook as Otto

Mark Dawson as Big Museum Guard

Gilbert Lewis as Museum Guard #1

George Bartenieff as Museum Guard #2

Charles White as Policeman

Albert Henderson as Prison Property Clerk (uncredited)

Burt Richards as Police Officer (uncredited)

Arnold Williams as Prisoner (uncredited)