Jake Gyllenhaal Robert Graysmith
Robert Downey Jr. Paul Avery
Mark Ruffalo David Toschi
June Diane Raphael Mrs. Toschi
Louis Phillips Executive Producer
Chloë Sevigny Melanie
Brian Cox Melvin Belli
Pell James Cecilia Shepard
Dermot Mulroney Martin Lee
David Fincher Director
Jimmi Simpson Mike Mageau
Donal Logue Ken Narlow
Drew Kunin Sound mixer
John Carroll Lynch Arthur Leigh Allen
Clea DuVall Linda del Buono
Elias Koteas Jack Mulanax
Candy Clark Carol Fisher
Anthony Edwards William Armstrong
Harris Savides Director of Photography
Adam Goldberg Duffy Jennings
Tom Verica Jim Dunbar
Angus Wall Editor
Matt Winston John Allen
Ione Skye Kathleen Johns (uncredited)
Karina Logue Woman
James Vanderbilt Screenplay, Producer
Zach Grenier Mel Nicolai
Richmond Arquette Zodiac 1 / Zodiac 2
Charles Fleischer Bob Vaughn
Patrick Scott Lewis Bryan Hartnell
Paul Schulze Sandy Panzarella
James LeGros George Bawart
John Getz Templeton Peck
Natalia de la Garza Digital Compositor
George Drakoulias Music Supervisor
Barry Livingston Copy Editor #3
Lee Norris Young Mike Mageau
Jason Wiles Lab Tech Dagitz
Bob Stephenson Zodiac 3
Mickey Giacomazzi Stunt Coordinator
Michael Rose Navy Project Leader
Jeff Daniel Phillips Informant
Victor J. Zolfo Set Decoration
Philip Baker Hall Sherwood Morrill
Ren Klyce Supervising Sound Editor, Sound Designer
Trish Almeida Key Hair Stylist
John Lacy Zodiac 4
John Ennis Terry Pascoe
David Parker Sound Re-Recording Mixer
Richard Hymns Supervising Sound Editor
Bud Davis Patrolman (uncredited)
Stacy Horn Costume Supervisor
Thomas Kopache Copy Editor #1
Joel Bissonnette Inspector Kracke
David Lee Smith Father
Adam Trese Detective #1
Ceán Chaffin Producer
Christopher John Fields Copy Editor #4
Laray Mayfield Casting
John R. Manocchia Rigging Gaffer
Richard Quinn Dialogue Editor
Cooper Thornton Internal Affairs Agent #1
Judith Drake Florence Douglas
Roy Lee Jones Distraught African American Male
Steve Hart Stunts
Edson Williams Visual Effects Supervisor
John Terry Charles Thieriot
Geoff Callan Patrolman Zelms
Brett Rickaby Detective Roy
John Mahon Riverside Captain
Michael Semanick Sound Re-Recording Mixer
Ciara Hughes Darlene Ferrin