| Dominic West | Det. James 'Jimmy' McNulty |
| John Doman | Dep. Comm. for Operations William A. Rawls |
| Idris Elba | Russell 'Stringer' Bell |
| Frankie Faison | Acting Commissioner Ervin H. Burrell |
| Aidan Gillen | Councilman Thomas 'Tommy' Carcetti |
| Wood Harris | Avon Barksdale |
| Deirdre Lovejoy | Asst. State's Atty. Rhonda Pearlman |
| Clarke Peters | Det. Lester Freamon |
| Wendell Pierce | Det. William 'Bunk' Moreland |
| Lance Reddick | Lt. Cedric Daniels |
| Andre Royo | Reginald 'Bubbles' Cousins |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Jim True-Frost | Det. Roland 'Prez' Pryzbylewski |
| Robert Wisdom | Maj. Howard 'Bunny' Colvin |
| Seth Gilliam | Sgt. Ellis Carver |
| Domenick Lombardozzi | Det. Thomas 'Herc' Hauk |
| J.D. Williams | Preston 'Bodie' Broadus |
| Michael Kenneth Williams | Omar Little |
| Corey Parker Robinson | Det. Leander Sydnor |
| Callie Thorne | Elena McNulty |
| Isiah Whitlock Jr. | State Sen. R. Clayton 'Clay' Davis |
| Tray Chaney | Malik 'Poot' Carr |
| Chad L. Coleman | Dennis 'Cutty' Wise |
| Benjamin Busch | Off. Anthony Colicchio |
| Jay Landsman | Lt. Dennis Mello |
| Delaney Williams | Sgt. Jay Landsman |
| Richard Burton | Sean 'Shamrock' McGinty |
| Brandon Fobbs | Fruit |
| Anwan Glover | Slim Charles |
| Mayo Best | Gerard |
| R. Emery Bright | Community Relations Sgt. |
| Clarence Clemons | Roman |
| Brandan T. Tate | Sapper |
| Maria Broom | Marla Daniels |
| Shamyl Brown | Donette |
| Brandy Burre | Theresa D'Agostino |
| Vera Holley | The Principal |
| Muna Otaru | Student in Registrar's Office |
| Antonio Cordova | Michael McNulty |
| Michael Kostroff | Maurice 'Maury' Levy |
| Eugene R. Little | Cutty's Boss |
| Michael Willis | Andy Krawczyk |
| Brian Anthony Wilson | Det. Vernon Holley |
| James E. Ash | Uniform Officer |
| Justin Burley | Justin |
| Vicki Jean Clark | Wife |
| Sal Darigo | Harry |
| Kahil Dotay | Undercover Detective |
| Alan Gates | West Point Policeman |
| Edward Bernard Green Jr. | Spider |
| Joilet Harris | Off. Caroline Massey |
| De'Rodd Hearns | Herbert De'Rodd 'Puddin' Johnson |
| Yaphet Kotto | Meeting Man |
| Marc Krinsky | Angelo Martin |
| Kay Lawal | Meeting Woman |
| Christopher Mann | Councilman Anthony 'Tony' Gray |
| Josh Adam Meyers | Dope Fiend |
| Ty Robinson | Street Dealer |
| Scott Ross | College Student #1 |
| Justin Ruff | Marlos crew |
| Melvin T. Russell | Jamal |
| Ryan Sands | Off. Lloyd 'Truck' Garrick |
| Kenny Shapiro | Prison Guard |
| Rico Sterling | Tyrell |
| Thomas W. Stewart | Husband |