 | Casey Affleck als Patrick Kenzie |
 | Michelle Monaghan als Angie Gennaro |
 | Morgan Freeman als Jack Doyle |
 | Ed Harris als Sgt. Det. Remy Bressant |
 | John Ashton als Det. Nick Poole |
 | Amy Ryan als Helene McCready |
 | Amy Madigan als Bea McCready |
 | Titus Welliver als Lionel McCready |
 | Michael Kenneth Williams als Devin |
 | Edi Gathegi als "Cheese" Jean Baptiste |
 | Mark Margolis als Leon Trett |
 | Madeline O'Brien als Amanda McCready |
 | Slaine als Bubba |
| Trudi Goodman als Roberta Trett |
 | Matthew Maher als Corwin Earle |
 | Jill Quigg als Dottie |
| Sean Malone als Skinny Ray Likanski |
 | Brian Scannell als Lenny |
 | Jay Giannone als Steve Penteroudakis |
| William Lee als Big Dave |
| William Marlowe als Fillmore Regular |
| Daniel DeMiller Jr. als Fillmore Regular |
| Kenneth Butler Jr. als Fillmore Regular |
| Stephen Curran als Fillmore Regular |
| Michael T. Blythe als Fillmore Regular |
| Bob J. Leary als Fillmore Regular |
 | Mike Pusateri als Fillmore Regular |
| Paul Sullivan als Fillmore Regular |
| John McColgam als Fillmore Regular |
| Nicholas Donovan als Kid on Bike |
| Joseph Thomas-O'Brien als Kid on Bike |
 | Jimmy LeBlanc als Chris Mullen |
| Mary Bounphasaysonh als Cheese's Girl |
 | Fanshen Cox als Doyle's Secretary |
| Kippy Goldfarb als Francine Doyle |
| Elizabeth Duff als Mrs. Bressant |
| Cathie Callanan als Mrs. Poole |
| Cameron Henry als Johnny Pietro |
| Bobby Curcuro als Bobby |
| Kevin Molis als Officer in Procession |
 | Robert Wahlberg als Interrogating Officer |
| Tom Kemp als Police Captain |
| Matt Podolske als Officer Riley |
| Joseph Flaherty als Murphy's Law Bartender |
 | Carla Antonino als Murphy's Law Waitress |
 | Peg Holzemer als Woman at Bar |
| Chelsea Ladd als Boston Girl |
| Josh Marchette als Dart Player |
| Tom McNeeley als Teamster at Bar |
| Paul Hornung als Newscaster |
 | Rena Maliszewski als Newscaster |
| Suzanne Schemm als Newscaster |
 | Lonnie Farmer als Newscaster |
 | Richard Snee als Newscaster |
 | Dale Place als Newscaster |
 | Gary Tanguay als Newscaster |
| Ted Reinstein als Field Reporter |
 | Celeste Oliva als Field Reporter |
| Patrick Shea als Field Reporter |
 | Lewis D. Wheeler als Field Reporter |
 | Michele Proude als Field Reporter |
| Tim Estiloz als Field Reporter |
| Karen Scalia als Field Reporter |
| John Belche als Field Reporter |
| Raymond Alongi als West Beckett Police Officer |
| Joey Vacchio als State Trooper |
 | Eamon Brooks als State Trooper |
| Vincent H. Carolan als State Trooper |
| Frank G. Sullivan als State Trooper |
| Karen Ahern als Reunited Police Officer |
 | Ellen Becker Gray als Gossipy Funeral Mourner (uncredited) |
| Shana Carr als Restaurant Patron / Family Member at Funeral (uncredited) |
 | Mark S. Cartier als Pantsless Reporter (uncredited) |
| Frank Durant als Neighbor (uncredited) |
 | John Franchi als Funeral Attendee (uncredited) |
| Alex Milne als Child at Playground (uncredited) |
 | Nicholas Purcell als Punk (uncredited) |
| Alan Resnic als Mourner at Funeral (uncredited) |
| Ben Affleck | Screenplay |
| Aaron Stockard | Screenplay |
| John Toll | Director of Photography |
| Alan Ladd Jr. | Producer |
| Dennis Lehane | Novel |
| Ben Affleck | Director |
| Sean Bailey | Producer |
| William Goldenberg | Editor |
| Claire Folger | Still Photographer |
| Donna Morong | Casting |
| Sharon Seymour | Production Design |
| P. Scott Sakamoto | Steadicam Operator |
| Kyra Friedman Curcio | Set Decoration |
| Chris Cornwell | Art Direction |
| Danton Rissner | Producer |
| Chay Carter | Co-Producer |
| Amanda Lamb | Associate Producer |
| Christian P. Minkler | Sound Re-Recording Mixer |
| J.M. Hunter | Art Department Coordinator |
| David Crockett | Executive Producer |
| Nancy Hancock | Makeup Artist |
| Mary L. Mastro | Hair Department Head |
| Jon Taylor | Sound Re-Recording Mixer |
| Deena Adair | Hairstylist |
| Trish Seeney | Makeup Artist |
| Nic Harcourt | Music Supervisor |
| Sally Boldt | Music Editor |
| Sheila Waldron | Script Supervisor |
| Harry Gregson-Williams | Original Music Composer |
| Alix Friedberg | Costume Design |
| Aaron Stockard | Associate Producer |
| Mark P. Stoeckinger | Supervising Sound Editor |
| John E. Jackson | Makeup Department Head |
| Conrad V. Brink Jr. | Special Effects Coordinator |
| Alan Rankin | Sound Designer |
| P. Scott Sakamoto | Camera Operator |
| Cort Hessler | Stunt Coordinator |
| Brenda McNally | Hairstylist |
| Kurt Smith | Leadman |
| Joe Galdo | Post Production Assistant |
| Ladd McIntosh | Orchestrator |
| Mathieu Reid | Color Timer |
| Hope Slepak | Costume Supervisor |
| Michael Tronick | Additional Editing |
| Nathaniel Stutz | Craft Service |
| Terrence Malick | Thanks |
| Brett M. Reed | First Assistant Editor |
| George Lee | Set Designer |
| Mark Driscoll | Visual Effects Producer |
| David Crockett | Unit Production Manager |
| Mike Thomas | Camera Operator |
| Steve DeBoer | Construction Foreman |
| Andy Simonson | Visual Effects Coordinator |
| Jim Stuebe | Production Sound Mixer |
| Kevin Hickman | Assistant Editor |
| Kevin Hyde | Boom Operator |
| Desiree Varni | Production Accountant |
| Jeff Valeri | Production Coordinator |
| Joseph Kearney | Construction Coordinator |
| Matt Damon | Thanks |
| Henrik Fett | Visual Effects Supervisor |
| Charles Harrington | Location Manager |
| Amy Cohn | Unit Publicist |
| Robert Martini | Transportation Coordinator |
| Jimmy Flynn | Transportation Captain |
| Tina Anderson | Post Production Supervisor |
| Vanessa Pyne | Art Department Assistant |
| Tracy R. Spiegel | Craft Service |
| Jerry Bruckheimer | Thanks |
| Manny Ramírez | Thanks |
| Nadia Aleyd | Casting Associate |
| Lisa Shaftel | Scenic Artist |
| John C. Stuver | Dialogue Editor |
| Jeff Largent | Sound Recordist |
| Glynna Grimala | Dialogue Editor |
| Jeffrey Paul Johnson | Property Master |
| Kerry Dean Williams | ADR Supervisor |
| Chris Hogan | Dialogue Editor |
| Christopher Surgent | First Assistant Director |
| Takahide Kawakami | Second Assistant Director |
| Deborah Newhall | Key Costumer |
| Tisha D. Nagel | Costumer |
| Parrish Kennington | Costumer |
| Taryn Weaver | Costumer |
| Patrick McArdle | First Assistant Camera |
| Nerses Gezalyan | Foley Mixer |
| James Moriana | Foley Artist |
| Jeffrey Wilhoit | Foley Artist |
| Greg Steele | ADR Mixer |
| Weldon Brown | ADR Mixer |
| David Boulton | ADR Mixer |
| Victor Ray Ennis | First Assistant Sound Editor |
| Jarred Waldron | Chief Lighting Technician |
| David Ghegan | Assistant Chief Lighting Technician |
| Ben Beaird | Key Grip |
| Russell Nordstedt | Best Boy Grip |
| Tony Campenni | Dolly Grip |
| Matt Power | Second Second Assistant Director |
| Helen Stergiou | First Assistant Accountant |
| Christopher Murphy | Video Assist Operator |
| Jonathan Woods | Storyboard Artist |
| Skip Kimball | Digital Intermediate Colorist |
| Mary Nelson-Duerrstein | Negative Cutter |
| Shauna Duggins | Stunt Double |
| Jarrett Simon | Utility Sound |
