 | Owen Wilson als John Beckwith |
 | Vince Vaughn als Jeremy Grey |
 | Christopher Walken als Secretary William Cleary |
 | Rachel McAdams als Claire Cleary |
 | Isla Fisher als Gloria Cleary |
 | Jane Seymour als Kathleen Cleary |
 | Ellen Albertini Dow als Grandma Mary Cleary |
 | Keir O'Donnell als Todd Cleary |
 | Bradley Cooper als Zachary 'Sack' Lodge |
 | Ron Canada als Randolph |
 | Henry Gibson als Father O'Neil |
 | Dwight Yoakam als Mr. Kroeger |
 | Rebecca De Mornay als Mrs. Kroeger |
 | David Conrad als Trap |
 | Jennifer Alden als Christina Cleary |
 | Geoff Stults als Craig Garthe |
 | Diora Baird als Vivian |
 | Kathryn Joosten als Chazz's Mom |
 | Naureen Zaim als Hindu Woman |
 | Norma Michaels als Old Irish Woman |
 | James Carville als Himself (uncredited) |
 | Will Ferrell als Chazz Reinhold (uncredited) |
 | John McCain als Himself (uncredited) |
 | Lindsay Schoneweis als Woman in Hat (uncredited) |
 | Kelsey Wedeen als Bridesmaid (uncredited) |
 | Rachel Sterling als Brunette |
 | Camille Anderson als Camille |
| Ivana Bozilovic als Ivana |
 | Tanaya Nicole als Woman at Jewish Reception |
| David Dobkin | Director |
| Peter Abrams | Producer |
| Cale Boyter | Executive Producer |
| Richard Brener | Executive Producer |
| Toby Emmerich | Executive Producer |
| Robert L. Levy | Producer |
| Andrew Panay | Producer |
| Guy Riedel | Executive Producer |
| Rolfe Kent | Original Music Composer |
| Julio Macat | Director of Photography |
| Mark Livolsi | Editor |
| Lisa Beach | Casting |
| Sarah Katzman | Casting |
| Barry Robison | Production Design |
| Kevin Constant | Art Direction |
| Garrett Lewis | Set Decoration |
| Denise Wingate | Costume Design |
| Palma Bellardoni | Art Department Coordinator |
| John Hartigan | Special Effects Coordinator |
| Julia Neighly | Visual Effects Coordinator |
| Julie Orosz | Visual Effects Producer |
| Thomas J. Smith | Visual Effects Supervisor |
| Joe Bucaro III | Stunt Coordinator |
| Lori Ayala-Read | Costume Supervisor |
| Johnetta Boone | Costume Supervisor |
| John Casey | Costume Supervisor |
| Senna Shanti | Set Costumer |
| Amanda Sroka | Set Costumer |
| Lori McCoy-Bell | Key Hair Stylist |
| Dennis Liddiard | Makeup Artist |
| Fiona Connon | Makeup Artist |
| Michael Davis | Construction Coordinator |
| Marc Figueroa | Greensman |
| Gary Isbell | Leadman |
| Darlene A. DiDonato | Location Scout |
| Robert Campbell | Painter |
| Stephanie J. Gordon | Set Designer |
| Trey Clinesmith | First Assistant Camera |
| Gary Dagg | Key Grip |
| Donovan Davis | Grip |
| Phil Pastuhov | Aerial Director of Photography |
| David Chameides | Steadicam Operator |
| Richard J. Cartwright | Still Photographer |
| Kim M. Ferry | Hairstylist |
| A.J. Brosto | Set Dressing Artist |
| Jed Smith | Additional Music |
| Bradley O'Donnell | Carpenter |
| Erik Proveaux | Chef |
| Ina Haybaeck-Rogers | Choreographer |
| Cory Foster | Craft Service |
| Morris Aroesti | Driver |
| Paul Prokop | Executive in Charge of Finance |
| Nelson C. Wright Jr. | Picture Car Coordinator |
| Jay Vinitsky | Post Production Supervisor |
| Jon Davidson | Production Controller |
| Tanner Almon | Production Office Assistant |
| Aaron Anderson | Propmaker |
| Sean Mannion | Property Master |
| Andrew Padilla | Security |
| Ericka Bryce | Set Medic |
| Denise A. Beale | Set Production Assistant |
| Christopher Sidor | Sound Recordist |
| Zach Dulli | Stand In |
| Mike Massa | Stunts |
| Krister C. Johnson | Transportation Captain |
| Anthony Canard | Transportation Co-Captain |
| James Lowder | Transportation Coordinator |
| Udi Nedivi | Unit Production Manager |
| John M. Pisani | Unit Publicist |
| Carl Cifarlio | Utility Stunts |
| Vincent Lascoumes | First Assistant Director |
| Marion Tumen | Script Supervisor |
| Jim Passon | Color Timer |
| Linda Di Franco | Dialogue Editor |
| Tim Cravens | Editorial Production Assistant |
| Lonnie S. Gatlin | Best Boy Electric |
| Tom Cantrell | Electrician |
| Kenny Schneider | Lighting Technician |
| Walter Nichols | Rigging Gaffer |
| Bryan Antin | Rigging Grip |
| John Strawbridge | Casting Associate |
| Erik Holmberg | Executive In Charge Of Production |
| Carol Flaisher | Location Manager |
| Rachel E. Prentiss | Production Accountant |
| Christopher K. Grap | Production Coordinator |
| Dave McMoyler | ADR Supervisor |
| Tom Hartig | Boom Operator |
| Randall Guth | First Assistant Sound Editor |
| Nick South | Music Editor |
| Tony Blondal | Orchestrator |
| Tim Chau | Sound Designer |
| David Grimaldi | Sound Effects Editor |
| John Rotondi | Sound Engineer |
| Mark Ulano | Sound Mixer |
| Tim Chau | Supervising Sound Editor |
| R.J. Harbour | Digital Compositors |
| Gina W. Bateman | Assistant Makeup Artist |
| Sandra Collier | Key Set Costumer |
| Jeffrey Pratt Gordon | On Set Dresser |
| Eric Richard Lasko | Additional Second Assistant Director |
| Christophe Le Chanu | Second Assistant Director |
| Michael Glynn | Assistant Property Master |
| David Beach | Construction Buyer |
| Matthew Richard Harris | Graphic Designer |
| Michael Hertlein | ADR Editor |
| Ron Bedrosian | ADR Mixer |
| Susan Cahill | ADR Recordist |
| James Moriana | Foley Artist |
| Nerses Gezalyan | Foley Mixer |
| David Escher | Special Effects Technician |
| Jimmy N. Roberts | Stunt Double |
| Rodney Veto | Best Boy Grip |
| Ryotaro Kinno | Camera Loader |
| Mike Connors | Dolly Grip |
| Craig Kohlhoff | Second Assistant Camera |
| Terri Douglas | ADR Voice Casting |
| Tom Dailey | Assistant Editor |
| Amy Pawlowski | Digital Intermediate Editor |
| Gary Burritt | Negative Cutter |
| Stephen Fischer | Assistant Location Manager |
| Ari Flaisher | Location Assistant |
| Rolfe Kent | Conductor |
| Jed Smith | Music Producer |
| Trevor Gilchrist | Music Programmer |
| Pia Howeth | Art Department Production Assistant |
| Brian Cooper | Assistant Production Coordinator |
| Bob E. Krattiger | Chief Lighting Technician |
| Tracy Dixon | Extras Casting |
| Carol Grant | Extras Casting Coordinator |
| Marybeth Martin-Eck | First Assistant Accountant |
| Kenneth Morton | Key Rigging Grip |
| Jim Swidarski | Payroll Accountant |
| Jason De Meo | Production Assistant |
| Katherine E. Beyda | Production Executive |
| Sarah Lorenz | Production Secretary |
| Sara Howell | Second Assistant Accountant |
| Julian Brain | Second Second Assistant Director |
| Terra Bliss | Digital Intermediate |
| Chris Ryan | CG Artist |
| Dick Ziker | Utility Stunts |
| Bob Fisher | Writer |
| Steve Faber | Writer |
