| Dominic West | Det. James 'Jimmy' McNulty |
| John Doman | Maj. William A. Rawls |
| Idris Elba | Russell 'Stringer' Bell |
| Frankie Faison | Dep. Comm. for Operations Ervin H. Burrell |
| Lawrence Gilliard Jr. | D'Angelo Barksdale |
| Wood Harris | Avon Barksdale |
| Deirdre Lovejoy | Asst. State's Atty. Rhonda Pearlman |
| Wendell Pierce | Det. William 'Bunk' Moreland |
| Lance Reddick | Lt. Cedric Daniels |
| Andre Royo | Reginald 'Bubbles' Cousins |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Peter Gerety | Judge Daniel Phelan |
| Seth Gilliam | Det. Ellis Carver |
| Domenick Lombardozzi | Det. Thomas 'Herc' Hauk |
| Clarke Peters | Det. Lester Freamon |
| Jim True-Frost | Det. Roland 'Prez' Pryzbylewski |
| Hassan Johnson | Roland 'Wee-Bey' Brice |
| Corey Parker Robinson | Det. Leander Sydnor |
| Michael B. Jordan | Wallace |
| J.D. Williams | Preston 'Bodie' Broadus |
| Tray Chaney | Malik 'Poot' Carr |
| Richard DeAngelis | Maj. Raymond Foerster |
| Michael Salconi | Det. Michael 'Sanny' Santangelo |
| Michael Kostroff | Maurice 'Maury' Levy |
| Melanie Nicholls-King | Cheryl |
| Delaney Williams | Sgt. Jay Landsman |
| Chris Clanton | Savino Bratton |
| Micaiah Jones | Wintell 'Little Man' Royce |
| Curtis Montez | Sterling |
| Tony D. Head | Maj. Bobby Reed |
| Clayton LeBouef | Wendell 'Orlando' Blocker |
| Edward T. Norris | Det. Edward Norris |
| Dick Stilwell | Commissioner Warren Frazier |
| Katana Lazet Hall | Savino's mother |
| Susan Rome | Asst. State's Atty. Ilene Nathan |
| Brian Anthony Wilson | Det. Vernon Holley |
| Christopher Glenn Wilson | DEA Agent |
| James E. Ash | Uniform Officer |
| Robert F. Colesberry | Det. Ray Cole |
| Derren Fuentes | Lt. Torret |
| John Holt Hall | DEA Agent In Charge |
| Julian Salazar | Antonio |