Brian Dennehy

John Wayne Gacy

Michael Riley

Joe 'Polock' Kozenczak

Margot Kidder

Rachel Grayson

Meg Foster

Linda Carlson

Martin Julien

Ted Koslo

Scott Hylands

Mike Paxton

John Boylan

Atkins

David Eisner

Williams

Tony De Santis

DeMarco

Mark Humphrey

King

Gary Reineke

Petrie

Tim Progosh

Morris

Danny Pawlick

Santori

Bruce Ramsay

Bragg

Brenda Bazinet

Alice Pearson

Liliane Clune

Marcia Kozenczak

Toby Proctor

Michael Kozenczak

Christopher Marren

Billy

Gerry Quigley

Walden

Nicholas Pasco

Barton

Michael Copeman

Chief Cameron

James Kee

Hoskins

Brigette Lawson

Pam

Jay Brazeau

Jake Burns

Cynthia Preston

Cindy Beck

Andrew Gillies

Vincent Austin

Kurt Reis

Waldron

Judith Goodwin

Mrs. Gant

Shawn Lawrence

Mr. Gant

Jacqueline Graham

Lorna Gant

Nicholas Shields

Christopher Gant

Sarah Gibney

Lisa Kozenczak

Aviva Magner

Debbie Kozenczak

Maureen McRae

Mrs. Trask

Timm Zemanek

Mr. Trask

Maria Ricossa

Helen Gacy

Darryl Palmer

Sheriff

Peter Langley

Mr. Miklovich

John Friesen

Detective #1

Ray Paisley

Illinois K-9 Officer

Brett Halsey

Stan Wilder

Elliott Smith

Gas Station Attendant

David Gardner

Judge

David Bolt

Asst. Principal Burke

Thomas Hauff

Foreman Hendricks

David McAree

Older Worker

J. Winston Carroll

Sergeant on Wabash Ave.

Don Ritchie

Detective on Shakespeare Ave.

Rudy Webb

Cemetery Staffer

Robbie Rox

Cicero Bar Owner

Larry Reynolds

Finger Lake Proprietor

Veliko Pajkovic

Man at Bus Station

John Granik

Narrator (voice)

Luis Guzmán

Waiter (uncredited)

Peter Kerenyi

Pool Player (uncredited)