Jake Gyllenhaal
Robert Graysmith
Anthony Edwards
William Armstrong
Robert Downey Jr.
Paul Avery
John Carroll Lynch
Arthur Leigh Allen
Dermot Mulroney
Martin Lee
Charles Fleischer
Bob Vaughn
Philip Baker Hall
Sherwood Morrill
James Le Gros
George Bawart
Richmond Arquette
Zodiac 1 / Zodiac 2
John Terry
Charles Thieriot
June Diane Raphael
Mrs. Toschi
Ciara Hughes
Darlene Ferrin
Lee Norris
Young Mike Mageau
Patrick Scott Lewis
Bryan Hartnell
Pell James
Cecilia Shepard
Jason Wiles
Lab Tech Dagitz
Charles Schneider
Cabbie / Paul Stine
Doan Ly
Belli's Housekeeper
Joel Bissonnette
Inspector Kracke
John Mahon
Riverside Captain
Jules Bruff
Catherine Allen
J. Patrick McCormack
Police Commissioner
Adam Goldberg
Duffy Jennings
Clea DuVall
Linda del Buono
Paul Schulze
Sandy Panzarella
Penny Wallace
Mulanax's Secretary
John Hemphill
Donald Cheney
Michel Francoeur
Man on Marquee
Thomas Kopache
Copy Editor #1
Barry Livingston
Copy Editor #3
Christopher John Fields
Copy Editor #4
Jack Samson
Young David Graysmith
Micah Sauers
David Graysmith
Zachary Sauers
Aaron Graysmith
Jessica Baltutis
Margot Graysmith
Peter Quartaroli
Patrolman Fouke
Geoff Callan
Patrolman Zelms
Michael Hungerford
Truck Driver
Anna Katarina
Society Woman
E.P. McKnight
Informant (Hall of Justice A)
Jeff Daniel Phillips
Informant
Cookie Crawford
Informant #8
Cassius M. Willis
Uniform Cop
Judith Drake
Florence Douglas
Phoebe Holston
Prison Guard
Marty Lodge
Pinole Foreman
Cooper Thornton
Internal Affairs Agent #1
Cazimir Milostan
Internal Affairs Agent #2
Charlotte Ferguson
Kathleen Johns' baby
Phoebe Ferguson
Kathleen Johns' baby
Kacey Malmsten
Kathleen Johns' baby
Karly Malmsten
Kathleen Johns' baby
Stanley B. Herman
Staff Editor
Roy Lee Jones
Distraught African American Male
Michael Rose
Navy Project Leader
James Joseph O'Neil
DOD Project Leader
Gloria Grant
Bettye Harden
Brett Rickaby
Detective Roy
Carter Evans
Newscaster #2
Bill Seward
TV News Anchor
Ione Skye
Kathleen Johns (uncredited)
David Winston Barge
Vallejo Desk Ofiicer (uncredited)
Hayati Akbas
Hardware Store Customer (uncredited)
Brad Carr
Camera Man (uncredited)
Mitchell Fink
Reporter (uncredited)
Erica Ford
Traveler (uncredited)
Tish Hicks
Informant (uncredited)
Danielle McKee
Prisoner (uncredited)
Derris Nile
Office Worker (uncredited)
Carmen Plumb
Janie (uncredited)
Callie Thompson
Child Witness (uncredited)
Bud Davis
Patrolman (uncredited)