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

Bruce Ramsay

Bragg

Brenda Bazinet

Alice Pearson

Christopher Marren

Billy

Gerry Quigley

Walden

Nicholas Pasco

Barton

Michael Copeman

Chief Cameron

Jay Brazeau

Jake Burns

Cynthia Preston

Cindy Beck

Andrew Gillies

Vincent Austin

Shawn Lawrence

Mr. Gant

Timm Zemanek

Mr. Trask

Maria Ricossa

Helen Gacy

John Friesen

Detective #1

Brett Halsey

Stan Wilder

Thomas Hauff

Foreman Hendricks

Rudy Webb

Cemetery Staffer

Luis Guzmán

Waiter (uncredited)