Warren Beatty
— Harley Rummel
Leslie Caron
— Michele O'Brien
Robert Cummings
— Dr. Philip Brock
Keenan Wynn
— Angelo Carelli
Lionel Stander
— Sam
Asa Maynor
— Rusty
Cathleen Nesbitt
— Mrs. Brock
Michael Bradley
— John Thomas
Warren Mitchell
— Frank Focus / Panel Moderator
Sydney Tafler
— Panel Participant
Michael Kane
— Staff Doctor
Riggs O'Hara
— Glue Sniffer
Mavis Villiers
— Rusty's Mother
Margaret Nolan
— Mail-Order Film Girl
Viviane Ventura
— Mail-Order Film Girl
George Moon
— Neighbour
Charlotte Holland
— Neighbour
Ferdy Mayne
— Vittorio Fettucini
Libby Morris
— Clinic Mother
Bessie Love
— Pet Shop Customer
Jill Adams
— Mrs. B.M. von Crispin
Donald Sutherland
— Autograph Seeking Father (uncredited)
Jo Anne Worley
— Autograph Seeking Mother (uncredited)
Anita Sharp-Bolster
— Mrs. Egan (uncredited)
Chuck Julian
— Grocery Clerk (uncredited)
Vera Goulet
— Nurse (uncredited)
Michael Chaplin
— Heathcliff – Beatnik (uncredited)
Pauline Chamberlain
— Woman in Audience (uncredited)