| Person | Type | Job | Role(s) |
|---|---|---|---|
 Addison Teague | Crew | Sound | Sound Effects Editor |
 Amy Schmiederer | Crew | Costume & Make-Up | Makeup Artist |
 Angus Wall | Crew | Editing | Editor |
Casey Storm | Crew | Costume & Make-Up | Costume Design |
 Ceán Chaffin | Crew | Production | Producer |
 Daniel M. Stillman | Crew | Production | Unit Production Manager |
David C. Hughes | Crew | Sound | Sound Effects Editor |
 David Fincher | Crew | Directing | Director |
 David Parker | Crew | Sound | Sound Re-Recording Mixer |
 David Shire | Crew | Sound | Original Music Composer |
 Donald Graham Burt | Crew | Art | Production Design |
Drew Kunin | Crew | Sound | Sound mixer |
Felicity Bowring | Crew | Costume & Make-Up | Makeup Department Head |
 George Drakoulias | Crew | Sound | Music Supervisor |
 Harris Savides | Crew | Camera | Director of Photography |
 James Vanderbilt | Crew | Writing | Screenplay, Producer |
John R. Manocchia | Crew | Lighting | Rigging Gaffer |
Keith P. Cunningham | Crew | Art | Art Direction |
Kelvin R. Trahan | Crew | Costume & Make-Up | Hair Department Head |
 Kristine Kelly | Crew | Directing | Script Supervisor |
 Laray Mayfield | Crew | Production | Casting |
Malcolm Fife | Crew | Sound | Dialogue Editor |
Mary Ellen Woods | Crew | Directing | First Assistant Director |
Merrick Morton | Crew | Camera | Still Photographer |
 Michael Semanick | Crew | Sound | Sound Re-Recording Mixer |
 Mickey Giacomazzi | Crew | Crew | Stunt Coordinator |
Mike Medavoy | Crew | Production | Producer |
Randall Poster | Crew | Sound | Music Supervisor |
 Ren Klyce | Crew | Sound | Sound Designer, Supervising Sound Editor |
 Richard Hymns | Crew | Sound | Supervising Sound Editor |
Richard Quinn | Crew | Sound | Dialogue Editor |
Stacy Horn | Crew | Costume & Make-Up | Costume Supervisor |
Victor J. Zolfo | Crew | Art | Set Decoration |
Arnold Messer | Crew | Production | Producer |
 Bradley J. Fischer | Crew | Production | Producer |
Bryan Lawson | Crew | Sound | Music Editor |
Louis Phillips | Crew | Production | Executive Producer |
Miia Kovero | Crew | Costume & Make-Up | Hairstylist |
 Robert Graysmith | Crew | Writing | Book |
Trish Almeida | Crew | Costume & Make-Up | Key Hair Stylist |
Jonathon Stevens | Crew | Sound | Music Editor |
Martin Erskine | Crew | Sound | Music Editor |
Sally Sue Beisel | Crew | Directing | Second Assistant Director |
 Adam Goldberg | Cast | Actor | Duffy Jennings |
 Adam Trese | Cast | Actor | Detective #1 |
 Anthony Edwards | Cast | Actor | William Armstrong |
 Barry Livingston | Cast | Actor | Copy Editor #3 |
 Betty Murphy | Cast | Actress | Informant |
 Bill Seward | Cast | Actor | TV News Anchor |
 Bob Stephenson | Cast | Actor | Zodiac 3 |
 Brett Rickaby | Cast | Actor | Detective Roy |
 Brian Cox | Cast | Actor | Melvin Belli |
Bud Davis | Cast | Actor | Patrolman (uncredited) |
 Candy Clark | Cast | Actress | Carol Fisher |
 Charles Fleischer | Cast | Actor | Bob Vaughn |
 Charles Schneider | Cast | Actor | Cabbie / Paul Stine |
 Chloë Sevigny | Cast | Actress | Melanie |
 Christopher John Fields | Cast | Actor | Copy Editor #4 |
 Clea DuVall | Cast | Actress | Linda del Buono |
 Cooper Thornton | Cast | Actor | Internal Affairs Agent #1 |
Dave Nemeth | Cast | Newscaster #4 | |
 David Lee Smith | Cast | Actor | Father |
 Dermot Mulroney | Cast | Actor | Martin Lee |
 Donal Logue | Cast | Actor | Ken Narlow |
 Ed Setrakian | Cast | Actor | Al Hyman |
 Elias Koteas | Cast | Actor | Jack Mulanax |
 Geoff Callan | Cast | Actor | Patrolman Zelms |
Gloria Grant | Cast | Actress | Bettye Harden |
 Ione Skye | Cast | Actress | Kathleen Johns (uncredited) |
 J. Patrick McCormack | Cast | Actor | Police Commissioner |
 JD Cullum | Cast | Actor | Director |
 Jake Gyllenhaal | Cast | Actor | Robert Graysmith |
 James Carraway | Cast | Actor | Shorty |
 James Le Gros | Cast | Actor | George Bawart |
 Jason Wiles | Cast | Actor | Lab Tech Dagitz |
 Jeff Daniel Phillips | Cast | Actor | Informant |
 Jimmi Simpson | Cast | Actor | Mike Mageau |
 Joel Bissonnette | Cast | Actor | Inspector Kracke |
 John Carroll Lynch | Cast | Actor | Arthur Leigh Allen |
 John Ennis | Cast | Actor | Terry Pascoe |
 John Getz | Cast | Actor | Templeton Peck |
 John Hemphill | Cast | Actor | Donald Cheney |
 John Lacy | Cast | Actor | Zodiac 4 |
 John Mahon | Cast | Actor | Riverside Captain |
 John Terry | Cast | Actor | Charles Thieriot |
 Judith Drake | Cast | Actress | Florence Douglas |
 Jules Bruff | Cast | Actress | Catherine Allen |
 Karina Logue | Cast | Actress | Woman |
 Lee Norris | Cast | Actor | Young Mike Mageau |
 Mark Ruffalo | Cast | Actor | David Toschi |
 Marty Lodge | Cast | Pinole Foreman | |
 Matt Winston | Cast | Actor | John Allen |
 Michael Rose | Cast | Actor | Navy Project Leader |
 Michel Francoeur | Cast | Actor | Man on Marquee |
 Paul Schulze | Cast | Actor | Sandy Panzarella |
 Peter Quartaroli | Cast | Actor | Patrolman Fouke |
 Philip Baker Hall | Cast | Actor | Sherwood Morrill |
Phoebe Ferguson | Cast | Kathleen Johns' baby | |
 Richmond Arquette | Cast | Actor | Zodiac 1 / Zodiac 2 |
 Robert Downey Jr. | Cast | Actor | Paul Avery |
 Rod Damer | Cast | FBI Codebreaker | |
 Stanley B. Herman | Cast | Actor | Staff Editor |
 Ted Garcia | Cast | Actor | Anchorman #1 |
 Thomas Kopache | Cast | Actor | Copy Editor #1 |
Tish Hicks | Cast | Informant (uncredited) | |
 Tom Verica | Cast | Actor | Jim Dunbar |
 Zach Grenier | Cast | Actor | Mel Nicolai |
 Anna Katarina | Cast | Actress | Society Woman |
Brad Carr | Cast | Actor | Camera Man (uncredited) |
Carmen Plumb | Cast | Actress | Janie (uncredited) |
 Cassius M. Willis | Cast | Actor | Uniform Cop |
 Cazimir Milostan | Cast | Actor | Internal Affairs Agent #2 |
 Ciara Hughes | Cast | Actress | Darlene Ferrin |
 Danielle McKee | Cast | Actress | Prisoner (uncredited) |
Derris Nile | Cast | Office Worker (uncredited) | |
 Doan Ly | Cast | Actress | Belli's Housekeeper |
Hayati Akbas | Cast | Hardware Store Customer (uncredited) | |
 James Joseph O'Neil | Cast | Actor | DOD Project Leader |
 June Diane Raphael | Cast | Actress | Mrs. Toschi |
 Patrick Scott Lewis | Cast | Bryan Hartnell | |
 Pell James | Cast | Actress | Cecilia Shepard |
 Roy Lee Jones | Cast | Actor | Distraught African American Male |
 Shane Woodson | Cast | Actor | Informant |
David Winston Barge | Cast | Vallejo Desk Ofiicer (uncredited) | |
Mitchell Fink | Cast | Actor | Reporter (uncredited) |
Michael Hungerford | Cast | Actor | Truck Driver |
M.F. Bernier | Cast | Detective #2 | |
 Zachary Sauers | Cast | Aaron Graysmith | |
Erica Ford | Cast | Actress | Traveler (uncredited) |
Callie Thompson | Cast | Actress | Child Witness (uncredited) |
Ken Narlow | Cast | Actor | Himself (archive footage) (uncredited) |
 Phoebe Holston | Cast | Actress | Prison Guard |
 Micah Sauers | Cast | David Graysmith | |
Penny Wallace | Cast | Mulanax's Secretary | |
Jack Samson | Cast | Young David Graysmith | |
 E.P. McKnight | Cast | Actress | Informant (Hall of Justice A) |
John Sarno | Cast | Actor | Donald Harden |
| Person | Type | Job | Role(s) |
