Jake Gyllenhaal character Robert Graysmith
Mark Ruffalo character Dave Toschi
Robert Downey Jr. character Paul Avery
Anthony Edwards character Bill Armstrong
Brian Cox character Melvin Belli
John Carroll Lynch character Arthur Leigh Allen
Richmond Arquette character Zodiac 1 / Zodiac 2
Bob Stephenson character Zodiac 3
John Lacy character Zodiac 4
Chloë Sevigny character Melanie
Ed Setrakian character Al Hyman
John Getz character Templeton Peck
John Terry character Charles Thieriot
Candy Clark character Carol Fisher
Elias Koteas character Jack Mulanax
Dermot Mulroney character Captain Martin Lee
Donal Logue character Captain Ken Narlow
June Diane Raphael character Mrs. Toschi
Ciara Hughes character Darlene Ferrin
Lee Norris character Young Mike Mageau
Patrick Scott Lewis character Bryan Hartnell
Pell James character Cecilia Shepard
Philip Baker Hall character Sherwood Morrill
David Lee Smith character Father
Jason Wiles character Lab Tech Dagitz
Charles Schneider character Cabbie / Paul Stine
James Carraway character Shorty
Tom Verica character Jim Dunbar
Jimmi Simpson character Mike Mageau
Doan Ly character Belli's Housekeeper
Karina Logue character Woman
Joel Bissonnette character Inspector Kracke
Zach Grenier character Mel Nicolai
John Mahon character Riverside Captain
Matt Winston character John Allen
Jules Bruff character Catherine Allen
John Ennis character Terry Pascoe
J. Patrick McCormack character Police Commissioner
Adam Goldberg character Duffy Jennings
James Le Gros character Officer George Bawart
Charles Fleischer character Bob Vaughn
Clea DuVall character Linda del Buono
Paul Schulze character Sandy Panzarella
Adam Trese character Detective #1
Penny Wallace character Mulanax's Secretary
John Hemphill character Donald Cheney
Michel Francoeur character Man on Marquee
Thomas Kopache character Copy Editor #1
Barry Livingston character Copy Editor #3
Christopher John Fields character Copy Editor #4
Stanley B. Herman character Staff Editor
Ione Skye character Kathleen Johns (uncredited)
Brett Rickaby character Detective Roy (uncredited)
Micah Sauers character David Graysmith (uncredited)
Hayati Akbas character Hardware Store Customer (uncredited)
David Winston Barge character Vallejo Desk Ofiicer (uncredited)
Geoff Callan character Patrolman Zelms (uncredited)
Brad Carr character Camera Man (uncredited)
JD Cullum character Director (uncredited)
Rod Damer character FBI Codebreaker (uncredited)
Judith Drake character Florence Douglas (uncredited)
Mark Falvo character Reporter (uncredited)
Mitchell Fink character Reporter (uncredited)
Erica Ford character Traveler (uncredited)
Ted Garcia character Anchorman (uncredited)
Gloria Grant character Bettye Harden (uncredited)
Tish Hicks character Informant (uncredited)
Phoebe Holston character Prison Guard (uncredited)
Michael Hungerford character Truck Driver (uncredited)
Janis Jones character Police Receptionist (uncredited)
Roy Lee Jones character Distraught African American Male (uncredited)
Anna Katarina character Society Woman (uncredited)
Marty Lodge character Pinole Foreman (uncredited)
Danielle McKee character Prisoner (uncredited)
Cazimir Milostan character Internal Affairs Agent (uncredited)
Betty Murphy character Informant (uncredited)
Dave Nemeth character Newscaster (uncredited)
Derris Nile character Office Worker (uncredited)
James Joseph O'Neil character DOD Project Leader (uncredited)
Jeff Daniel Phillips character Informant (uncredited)
Carmen Plumb character Janie (uncredited)
Peter Quartaroli character Patrolman Fouke (uncredited)
Michael Rose character Navy Project Leader (uncredited)
Jack Samson character Young David Graysmith (uncredited)
Zachary Sauers character Aaron Graysmith (uncredited)
Bill Seward character TV News Anchor (uncredited)
Callie Thompson character Child Witness (uncredited)
Cooper Thornton character Internal Affairs Agent (uncredited)
Cassius M. Willis character Uniform Cop (uncredited)
Shane Woodson character Informant (uncredited)
