| Dominic West | Off. James 'Jimmy' McNulty |
| John Doman | Dep. Comm. for Operations William A. Rawls |
| Frankie Faison | Commissioner Ervin H. Burrell |
| Aidan Gillen | Mayor Thomas 'Tommy' Carcetti |
| Deirdre Lovejoy | Asst. State's Atty. Rhonda Pearlman |
| Clarke Peters | Det. Lester Freamon |
| Wendell Pierce | Det. William 'Bunk' Moreland |
| Lance Reddick | Col. Cedric Daniels |
| Andre Royo | Reginald 'Bubbles' Cousins |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Jim True-Frost | Roland 'Prez' Pryzbylewski |
| Robert Wisdom | Howard 'Bunny' Colvin |
| Seth Gilliam | Sgt. Ellis Carver |
| Domenick Lombardozzi | Sgt. Thomas 'Herc' Hauk |
| Reg E. Cathey | Norman Wilson |
| Chad L. Coleman | Dennis 'Cutty' Wise
(credit only) |
| Jamie Hector | Marlo Stanfield |
| Glynn Turman | Former Mayor Clarence V. Royce
(credit only) |
| J.D. Williams | Preston 'Bodie' Broadus
(as JD Williams) |
| Michael Kenneth Williams | Omar Little
(as Michael K. Williams) |
| Corey Parker Robinson | Det. Leander Sydnor
(credit only) |
| Isiah Whitlock Jr. | State Sen. R. Clayton 'Clay' Davis |
| Jermaine Crawford | Duquan 'Dukie' Weems |
| Maestro Harrell | Randy Wagstaff |
| Julito McCullum | Namond Brice |
| Tristan Mack Wilds | Michael Lee
(as Tristan Wilds) |
| Gbenga Akinnagbe | Chris Partlow |
| Robert F. Chew | Joseph 'Proposition Joe' Stewart |
| Anwan Glover | Slim Charles |
| Method Man | Melvin 'Cheese' Wagstaff |
| Al Brown | Col. Stanislaus Valchek |
| Jay Landsman | Lt. Dennis Mello |
| Delaney Williams | Sgt. Jay Landsman |
| Jonnie Brown | Off. Eddie Walker
(as Jonnie Louis Brown) |
| Rashad Orange | Sherrod |
| Ramon Rodriguez | Renaldo |
| Thuliso Dingwall | Kenard |
| Rakiya Orange | Charlene Young |
| Jason Wharton | Albert Stokes |
| Stacie Davis | Ms. Duquette |
| Dan De Luca | David Parenti
(as Dan DeLuca) |
| Susan Duvall | Assistant Principal Marcia Donnelly
(as Tootsie Duvall) |
| Sandi McCree | De'Londa Brice |
| Felicia Pearson | Felicia 'Snoop' Pearson |
| Franklin Ojeda Smith | Minister |
| Felix Stevenson | Reverend Frank Reid |
| Edward T. Norris | Det. Edward Norris
(as Ed Norris) |
| Michael Salconi | Off. Michael 'Sanny' Santangelo |
| Gregory L. Williams | Det. Michael Crutchfield |
| Brian Anthony Wilson | Det. Vernon Holley |
| Yolanda Gaskins | School Board Representative |
| David E. Goodman | Budget Director
(as David Goodman) |
| Mark Joy | Ed Bowers |
| Michael Willis | Andy Krawczyk |
| Nathan Corbett | Donut |
| De'Ante McCullough | Boy
(as DeAnte McCullough) |
| Jasmine Pitts | Miss Rennert |
| Corbin Smith | Monell |
| Michael Norbin | |
| Michael Ahl | Detective
(uncredited) |
| Bobby J. Brown | Off. Bobby Brown
(uncredited) |
| Armando Cadogan Jr. | Bubbles' Tormentor
(uncredited) |
| Enrique Chicas | Bailiff
(uncredited) |
| Michael Coley | Kwame
(uncredited) |
| Davon Cooper | Darnell Tyson
(uncredited) |
| James Cottingham | Detective
(uncredited) |
| Shamika Cotton | Raylene Lee
(uncredited) |
| Sheila Cutchlow | Miss Sheperdson
(uncredited) |
| Derek Horton | Off. Brian Baker
(uncredited) |
| Destiny Jackson-Evans | Crystal Judkins
(uncredited) |
| Na'Dria Jennings | Chandra Porter
(uncredited) |
| Kamal Jones | Older Cop
(uncredited) |
| Taylor King | Zenobia Dawson
(uncredited) |
| Joey Odoms | School Boy
(uncredited) |
| Rodney Roldan | Young Cop
(uncredited) |
| Ryan Sands | Off. Lloyd 'Truck' Garrick
(uncredited) |
| Kevin L Simmons | Detective
(uncredited) |
| Corey Sorenson | Young Cop
(uncredited) |