| Dominic West | Off. James 'Jimmy' McNulty |
| John Doman | Dep. Comm. for Operations William A. Rawls
(credit only) |
| Frankie Faison | Commissioner Ervin H. Burrell
(credit only) |
| Aidan Gillen | Councilman Thomas 'Tommy' Carcetti |
| Deirdre Lovejoy | Asst. State's Atty. Rhonda Pearlman |
| Clarke Peters | Det. Lester Freamon |
| Wendell Pierce | Det. William 'Bunk' Moreland |
| Lance Reddick | Maj. Cedric Daniels |
| Andre Royo | Reginald 'Bubbles' Cousins
(credit only) |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Jim True-Frost | Roland 'Prez' Pryzbylewski |
| Robert Wisdom | Howard 'Bunny' Colvin
(credit only) |
| Seth Gilliam | Sgt. Ellis Carver |
| Domenick Lombardozzi | Det. Thomas 'Herc' Hauk |
| Reg E. Cathey | Norman Wilson |
| Chad L. Coleman | Dennis 'Cutty' Wise
(credit only) |
| Jamie Hector | Marlo Stanfield |
| Glynn Turman | Mayor Clarence V. Royce |
| J.D. Williams | Preston 'Bodie' Broadus
(as JD Williams) |
| Michael Kenneth Williams | Omar Little
(as Michael K. Williams) (credit only) |
| Corey Parker Robinson | Det. Leander Sydnor |
| 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 |
| Susan Duvall | Assistant Principal Marcia Donnelly
(as Tootsie Duvall) |
| Henri Edmonds | School Lecturer |
| Richard Hidlebird | Principal Claudell Withers |
| Christopher Mann | Councilman Anthony 'Tony' Gray |
| Megan Anderson | Jen Carcetti |
| Brandy Burre | Theresa D'Agostino |
| Sam Coppola | Former Mayor 'Young Tony' |
| Joilet Harris | Off. Caroline Massey
(as Joliet F. Harris) |
| Brandon Fobbs | Fruit |
| Anwan Glover | Slim Charles |
| Norman Jackson | Lex |
| Cleo Reginald Pizana | Chief of Staff Coleman Parker |
| Tyrell Baker | Little Kevin |
| Nathan Corbett | Donut |
| Felicia Pearson | Felicia 'Snoop' Pearson |
| Karen Vicks | Gerry |
| Cynthia Webb | Teacher #2
(as Cynthia Webb-Manly) |
| Benjamin Busch | Off. Anthony Colicchio |
| Jay Landsman | Lt. Dennis Mello |
| Edward T. Norris | Det. Edward Norris
(as Ed Norris) |
| Jason Parker | Off. Reggie Leddett |
| Michael Salconi | Off. Michael 'Sanny' Santangelo |
| Tyreeka Freamon | School Receptionist |
| Thomas C. Hessenauer | Teacher #1 |
| Paul L. Nolan | Hardware Store Employee
(as Paul Nolan) |
| Jim Rood | Patrolman |
| Gene Terinoni | Lt. Jimmy Asher |
| Michael Ahl | Detective
(uncredited) |
| Marlyne Barrett | Council President Nerese Campbell
(uncredited) |
| Ted Borodaeff | Campaigner
(uncredited) |
| Tamieka Chavis | Royce's Assistant
(uncredited) |
| Enrique Chicas | Bailiff
(uncredited) |
| Michael Coley | Corner Boy
(uncredited) |
| Thomas Joe Craig | Construction Foreman
(uncredited) |
| Thuliso Dingwall | Kenard
(uncredited) |
| Dave Ehrman | Campaigner
(uncredited) |
| Denise Hart | Miss Anna Jeffries
(uncredited) |
| Chris James | Carcetti's Driver
(uncredited) |
| Mark Joy | Ed Bowers
(uncredited) |
| Atif Lanier | Western District Police Officer
(uncredited) |
| Marcus LaRon | Police Officer
(uncredited) |
| Traci Law | Teacher
(uncredited) |
| Brian E. McLarney | Off. Brian McLarney
(uncredited) |
| Kwame Patterson | 'Monk' Metcalf
(uncredited) |
| Ryan Sands | Off. Lloyd 'Truck' Garrick
(uncredited) |
| Derek A. Smith | Construction Foreman
(uncredited) |
| Shaunté Usual | Patrice
(uncredited) |
| Michael Willis | Andy Krawczyk
(uncredited) |