| 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 |
| Glynn Turman | Mayor Clarence V. Royce |
| Isiah Whitlock Jr. | State Sen. R. Clayton 'Clay' Davis |
| Chad L. Coleman | Dennis 'Cutty' Wise |
| Jamie Hector | Marlo Stanfield |
| Michael Hyatt | Brianna Barksdale |
| Leo Fitzpatrick | Johnny Weeks |
| Delaney Williams | Sgt. Jay Landsman |
| Kelli R. Brown | Kimmy |
| Benjamin Busch | Off. Anthony Colicchio |
| Robert F. Chew | Joseph 'Proposition Joe' Stewart |
| Jay Landsman | Lt. Dennis Mello |
| Ernest Waddell | Dante |
| Mayo Best | Gerard |
| Richard Burton | Sean 'Shamrock' McGinty |
| Anwan Glover | Slim Charles |
| Addison Switzer | Country |
| Brandan T. Tate | Sapper |
| Brandy Burre | Theresa D'Agostino |
| Richard DeAngelis | Col. Raymond Foerster |
| Christopher Mann | Councilman Anthony 'Tony' Gray |
| Cleo Reginald Pizana | Chief of Staff Coleman Parker |
| Michael Salconi | Off. Michael 'Sanny' Santangelo |
| Antonio Cordova | Michael McNulty |
| Michael Kostroff | Maurice 'Maury' Levy |
| Melvin Williams | Deacon |
| Michael Willis | Andy Krawczyk |
| Eric G. Ryan | Sean McNulty |
| Gbenga Akinnagbe | Chris Partlow |
| Mike D. Anderson | Ghost |
| Ken Arnold | Car Theft Reporting Lt. |
| R. Emery Bright | Community Relations Sgt. |
| Enrique Chicas | Bailiff |
| Vicki Jean Clark | Business Woman |
| Christopher Haley | Math Teacher |
| Eli Harris | Lieutenant |
| Tamara Johnson | Lieut. Cindy Lowry |
| Robert Neal Marshall | Comstat Police Major |
| Felicia Pearson | Felicia 'Snoop' Pearson |
| Vito Pietanza | FBI Agent |
| Lawrence Cameron Steele | Police Lieutenant |
| Thomas W. Stewart | Businessman |
| Troj Strickland | Ricardo 'Fat Face Rick' Hendrix |
| Edonis Washington | Latroy |
| Chester West | Shift Lt. Dent |