Ellen Burstyn character Chris MacNeil
Linda Blair character Regan Teresa MacNeil
Max von Sydow character Father Lankester Merrin
Lee J. Cobb character Lt. William F. Kinderman
Kitty Winn character Sharon Spencer
Jack MacGowran character Burke Dennings
Jason Miller character Father Damien Karras
William O'Malley character Father Joseph Dyer
Barton Heyman character Dr. Samuel Klein
Peter Masterson character Dr. Barringer
Rudolf Schündler character Karl
Gina Petrushka character Willi
Robert Symonds character Dr. Taney
Arthur Storch character Psychiatrist
Thomas Bermingham character Tom
Vasiliki Maliaros character Mary Karras
Titos Vandis character Uncle John
John Mahon character Language Lab Director
Wallace Rooney character Bishop Michael
Ron Faber character Chuck / Demon (voice)
Donna Mitchell character Mary Jo Perrin
Roy Cooper character Jesuit Dean
Robert Gerringer character Senator at Party
Mercedes McCambridge character Demon (voice)
Paul Bateson character Radiologist's Assistant (uncredited)
Elinore Blair character Nurse (uncredited)
William Peter Blatty character The Producer (uncredited)
Mary Boylan character First Mental Patient (uncredited)
Dick Callinan character Astronaut (uncredited)
Mason Curry character Doctor (voice) (uncredited)
Toni Darnay character Violent psychotic patient (uncredited)
Eileen Dietz character Demon / Regan Double (uncredited)
Joanne Dusseau character Senator's Wife (uncredited)
Bernard Eismann character Minor Role (uncredited)
Beatrice Hunter character Minor Role (uncredited)
Yvonne Jones character Bellevue Nurse (uncredited)
Don LaBonte character Minor Role (uncredited)
Barton Lane character Angiography Doctor (uncredited)
Ann Miles character Spiderwalk (uncredited)
John Nicola character Priest (uncredited)
Vincent Russell character Subway Vagrant (uncredited)
Gerard F. Yates character Priest Singing Around Piano at Party (uncredited)