To take down South Boston's Irish Mafia, the police send in one of their own to infiltrate the underworld, not realizing the syndicate has done likewise. While an undercover cop curries favor with the mob kingpin, a career criminal rises through the police ranks. But both sides soon discover there's a mole among them.
| Directing | Martin Scorsese | Director |
| Camera | Michael Ballhaus | Director of Photography |
| Editing | Thelma Schoonmaker | Editor |
| Production | Ellen Lewis | Casting |
| Writing | William Monahan | Screenplay |
| Production | Brad Grey | Producer |
| Production | Brad Pitt | Producer |
| Production | Graham King | Producer |
| Costume & Make-Up | Sandy Powell | Costume Design |
| Art | Kristi Zea | Production Design |
| Art | Teresa Carriker-Thayer | Art Direction |
| Art | Leslie E. Rollins | Set Decoration |
| Costume & Make-Up | Kathryn Blondell | Hairstylist |
| Costume & Make-Up | Kay Georgiou | Hairstylist |
| Costume & Make-Up | Johnny Villanueva | Hairstylist |
| Costume & Make-Up | Joy Zapata | Hairstylist |
| Costume & Make-Up | Michael Germain | Makeup Artist |
| Costume & Make-Up | Sian Grigg | Makeup Artist |
| Costume & Make-Up | Christine Beveridge | Makeup Artist |
| Costume & Make-Up | Donald Mowat | Makeup Artist |
| Costume & Make-Up | John Caglione Jr. | Makeup Artist |
| Art | Erik Knight | Art Department Coordinator |
| Art | Marion Kolsby | Assistant Art Director |
| Art | Robert Thayer | Assistant Art Director |
| Art | Theodore Suchecki | Construction Coordinator |
| Sound | Philip Stockton | Supervising Sound Editor |
| Sound | Eugene Gearty | Supervising Sound Editor |
| Sound | Eugene Gearty | Sound Effects Editor |
| Sound | Allan Zaleski | Sound Effects Editor |
| Sound | Tom Fleischman | Sound Re-Recording Mixer |
| Crew | Steven Kirshoff | Special Effects Coordinator |
| Visual Effects | Ron Ames | Visual Effects Producer |
| Visual Effects | Robert Legato | Visual Effects Supervisor |
| Crew | G. A. Aguilar | Stunt Coordinator |
| Camera | Thomas Lappin | Camera Operator |
| Camera | Bruce MacCallum | Camera Operator |
| Camera | Andrew Rowlands | Camera Operator |
| Camera | Andrew Cooper | Still Photographer |
| Costume & Make-Up | David Davenport | Costume Supervisor |
| Costume & Make-Up | Thomas Stokes | Costume Supervisor |
| Editing | Devin Sterling | Digital Intermediate |
| Sound | Tass Filipos | Music Editor |
| Sound | Jennifer Dunnington | Music Editor |
| Crew | Robert Martini | Transportation Coordinator |
| Directing | Martha Pinson | Script Supervisor |
| Crew | Tim Monich | Dialect Coach |
| Production | Carla Raij | Location Manager |
| Crew | Larry Kaplan | Unit Publicist |
| Directing | Joseph P. Reidy | Assistant Director |
| Visual Effects | David Ebner | Visual Effects Supervisor |
| Art | Susan Perlman | Set Decoration |
| Production | G. Mac Brown | Executive Producer |
| Production | Doug Davison | Executive Producer |
| Production | Roy Lee | Executive Producer |
| Crew | Brian Ricci | Special Effects |
| Crew | Eric Weinstein | Actor's Assistant |
| Lighting | Timothy Healy | Electrician |
| Crew | Paul A. Levin | Post Production Supervisor |
| Crew | Michael Arthur | Stunts |
| Crew | William 'Billy Jack' Jakielaszek | Special Effects |
| Crew | Lisa Shaftel | Scenic Artist |
| Art | Joseph S. Alfieri | Construction Coordinator |
| Art | Robert Griffon Jr. | Property Master |
| Sound | Philip Stockton | Dialogue Editor |
| Sound | Jac Rubenstein | Dialogue Editor |
| Crew | George B. Colucci Jr. | Stunts |
| Crew | Blaise Corrigan | Stunts |
| Crew | Lauren Hayward | Stunts |
| Crew | Janet Paparazzo | Stunts |
| Crew | Peewee Piemonte | Stunts |
| Crew | Jodi Michelle Pynn | Stunts |
| Crew | Shawnna Thibodeau | Stunts |
| Crew | Joseph Zamparelli | Stunt Driver |
| Sound | Jeffrey Stern | ADR Supervisor |
| Sound | Marissa Littlefield | ADR Supervisor |
| Sound | Howard Shore | Original Music Composer |
| Sound | Marko Costanzo | Foley Artist |
| Sound | Jamie Baker | Foley Editor |
| Sound | Kam Chan | Foley Editor |
| Crew | Chris Cenatiempo | Stunts |
| Directing | G. A. Aguilar | Second Unit Director |
| Writing | Felix Chong | Original Film Writer |
| Writing | Alan Mak | Original Film Writer |
| Crew | Alan Mak | Other |
| Crew | Andrew Lau Wai-Keung | Other |
| Production | Emma Tillinger Koskoff | Associate Producer |
| Art | David Swayze | Assistant Art Director |
