 | Casey Affleck als Lee Chandler |
 | Michelle Williams als Randi Chandler |
 | Kyle Chandler als Joe Chandler |
 | Lucas Hedges als Patrick Chandler |
 | C.J. Wilson als George |
 | Heather Burns als Jill |
 | Tate Donovan als Hockey Coach |
 | Josh Hamilton als Wes (Joe's Lawyer) |
 | Anna Baryshnikov als Sandy |
 | Matthew Broderick als Jeffrey |
 | Gretchen Mol als Elise Chandler |
 | Ben O'Brien als Young Patrick Chandler |
 | Richard Donelly als Mr. Martinez (1st Tenant) |
| Virginia Loring Cooke als Mrs. Groom (2nd Tenant) |
 | Quincy Tyler Bernstine als Marianne (3rd Tenant) |
 | Missy Yager als Mrs. Olsen (4th Tenant) |
 | Stephen Henderson als Mr. Emery |
| Ben Hanson als Bartender |
 | Mary Mallen als Sharon |
 | Lewis D. Wheeler als 1st Businessman at Bar |
 | Anthony Estrella als 2nd Businessman at Bar |
 | Susan Pourfar als Nurse Irene |
 | Robert Sella als Dr. Muller |
 | Ruibo Qian als Dr. Bethany |
 | Tom Kemp als Stan Chandler |
 | Chloe Dixon als Suzy Chandler |
 | Ellie Teves als Karen Chandler |
| Paul Meredith als Paul (Assistant Principal) |
| Carolyn Pickman als Paul's Assistant |
 | Christian J. Mallen als CJ |
 | Oscar Wahlberg als Joel |
 | Kara Hayward als Silvie |
 | Wendy Overly als Wes's Assistant |
 | Shawn Fitzgibbon als Tom Doherty (Ping-Pong Player) |
| Glenn McKiel als Manchester Police Chief |
 | Joe Stapleton als Fire Marshall |
 | Brian Chamberlain als Investigating Detective |
 | Kenneth Lonergan als Manchester Pedestrian |
| Jackson Damon als Otto |
 | Jami Tennille als Janine |
 | Liam McNeill als Josh (Randi's Husband) |
 | Allyn Burrows als Father Martin |
| Nellie Lonergan als 1st Girl at School ("Godspell") |
| Brian A. White als Jerry (Guy in Boat Yard Office) |
 | Erica McDermott als Sue (Angry Boss in Boat Yard Office) |
 | Danae Nason als Rachel (Randi's Friend) |
| Frank Garvin als Homeowner |
 | Kt Baldassaro als Bar Patron (uncredited) |
 | William Bornkessel als George's Son |
| Kenneth Lonergan | Director |
| Kenneth Lonergan | Writer |
| Jody Lee Lipes | Director of Photography |
| Jennifer Lame | Editor |
| Lesley Barber | Original Music Composer |
| Douglas Aibel | Casting |
| Ruth de Jong | Production Design |
| Jourdan Henderson | Art Direction |
| Florencia Martin | Set Decoration |
| Melissa Toth | Costume Design |
| Carolyn Pickman | Casting |
| Henry Russell Bergstein | Casting Associate |
| Matt Bouldry | Casting Associate |
| Dann Fink | ADR Voice Casting |
| Zach Zatet | Casting Assistant |
| Lauren Beck | Producer |
| Matt Damon | Producer |
| Chris Moore | Producer |
| Gigi Pritzker | Producer |
| Kimberly Steward | Producer |
| Kevin J. Walsh | Producer |
| Brannon Smithwick | Art Department Assistant |
| Morgan Kling | Property Master |
| Beth Anderson | Assistant Property Master |
| Andrea Ulrich | Script Supervisor |
| Mick Gormaley | Music Editor |
| Linda Cohen | Music Supervisor |
| Joanna Murphy | Assistant Costume Designer |
| Amy Pickering | Costume Supervisor |
| Alanna Keenan | Set Costumer |
| Susanna Brown | Tailor |
| Petr Hlinomaz | Camera Operator |
| Terrence Hayes | Camera Operator |
| Brant S. Fagan | Steadicam Operator |
| Claire Folger | Still Photographer |
| Joshua Dreyfus | Gaffer |
| Robert Kelly | Dolly Grip |
| Patrick Quinn | First Assistant Camera |
| Julien Zeitouni | First Assistant Camera |
| Warren A. Weberg | Key Grip |
| Michael Ricci | Special Effects Coordinator |
| Julius Horsthuis | Visual Effects Supervisor |
| Dan Edelstein | ADR Editor |
| Mark DeSimone | ADR & Dubbing |
| Peter Stevenson | Boom Operator |
| Leslie Bloome | Foley |
| Joanna Fang | Foley |
| Roland Vajs | Foley Editor |
| Jacob Ribicoff | Sound Designer |
| Jacob Ribicoff | Supervising Sound Editor |
| Frank Barbosa | Key Hair Stylist |
| Liz Bernstrom | Makeup Department Head |
| Sherryn Smith | Key Makeup Artist |
| Rob Fitz | Makeup Artist |
| Ivan Barahona | Digital Intermediate |
| Christina Delerme | Digital Intermediate |
| Joey Handy | Digital Intermediate |
| Jack Lewars | Digital Intermediate |
| John Krasinski | Executive Producer |
| Alexa Zimmerman | Dialogue Editor |
| Michael Fuchs | Steadicam Operator |
| Michael J. Moore | First Assistant Director |
| Ryan Stowell | Co-Producer |
| Josh Godfrey | Executive Producer |
| Declan Baldwin | Executive Producer |
| Bill Migliore | Executive Producer |
| Declan Baldwin | Unit Production Manager |
| David Blazina | Second Assistant Director |
