| Dominic West | Det. James 'Jimmy' McNulty |
| Reg E. Cathey | Norman Wilson |
| John Doman | Acting Commissioner William A. Rawls |
| Aidan Gillen | Mayor Thomas 'Tommy' Carcetti |
| Clark Johnson | City Editor Augustus 'Gus' Haynes |
| Deirdre Lovejoy | Asst. State's Atty. Rhonda Pearlman |
| Tom McCarthy | Scott Templeton |
| Clarke Peters | Det. Lester Freamon |
| Wendell Pierce | Det. William 'Bunk' Moreland |
| Lance Reddick | Dep. Comm. for Operations Cedric Daniels |
| Andre Royo | Reginald 'Bubbles' Cousins |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Seth Gilliam | Sgt. Ellis Carver |
| Domenick Lombardozzi | Thomas 'Herc' Hauk |
| Michael Kenneth Williams | Omar Little |
| Gbenga Akinnagbe | Chris Partlow |
| Jamie Hector | Marlo Stanfield |
| Neal Huff | Chief of Staff Michael Steintorf |
| Jermaine Crawford | Duquan 'Dukie' Weems |
| Corey Parker Robinson | Det. Leander Sydnor |
| Tristan Mack Wilds | Michael Lee |
| Michael Kostroff | Maurice 'Maury' Levy |
| Michelle Paress | Alma Gutierrez |
| Isiah Whitlock Jr. | State Sen. R. Clayton 'Clay' Davis |
| Amy Ryan | Off. Beatrice 'Beadie' Russell |
| Tray Chaney | Malik 'Poot' Carr |
| Felicia Pearson | Felicia 'Snoop' Pearson |
| Marlyne Barrett | Council President Nerese Campbell |
| Megan Anderson | Jen Carcetti |
| Benay Berger | FBI Supervisor Amanda Reese |
| Doug Olear | FBI Spec. Agent Terrance 'Fitz' Fitzhugh |
| Joe Urla | U.S. Attorney for the District of Maryland |
| David Costabile | Managing Editor Thomas Klebanow |
| Todd Scofield | Jeff Price |
| Brandon Young | Mike Fletcher |
| Michael Stone Forrest | Det. Frank Barlow |
| Edward T. Norris | Det. Edward Norris |
| Gregory L. Williams | Det. Michael Crutchfield |
| Bobby J. Brown | Off. Bobby Brown |
| Rick Otto | Off. Kenneth Dozerman |
| Ryan Sands | Off. Lloyd 'Truck' Garrick |
| Dave Ettlin | Dave Ettlin |
| Donald Neal | Rewrite Man Jay Spry |
| Robert Poletick | Metro Editor Steven Luxenberg |
| Jim Ancel | Man |
| David E. Goodman | Budget Director |
| Robert G. McKay | Rep. Albert Upshaw |
| William F. Zorzi | Bill Zorzi |
| Connor Aikin | Jack Russell |
| Keenon Brice | Aaron 'Bug' Manigault |
| Aubrey Deeker Hernandez | Terry Hanning |
| Thuliso Dingwall | Kenard |
| Reggie Alvin Green | Arabber |
| Leroy Graves Jr. | Man |
| Amy Lee | Store Owner |
| Russ Widdall | Ron Lowenthal |
| Curt Boushel | Andy |
| Joe Inscoe | FBI Deputy Director Arthur Tolan |
| William R. Johnson | FBI Agent |
| Paul Morella | FBI Profiler |
| Dennis Hill | Det. Christeson |
| Melody Williams | Woman at Crime Scene #1 |
| Melvina Williams | Woman at Crime Scene #2 |
| Marybeth Wise | Off. Karen |
| Michael Ahl | Detective |
| Sophia Ayoud | Cary Russell |
| Glenn Beck | Self |
| Anthony Bosco | The Sun Copy Editor |
| Larry Carter | Reporter |
| Greg Coale | Reporter |
| Philip DePalo | Uniformed Police Officer |
| Art Hall | Reporter |
| Marcus Nel-Jamal Hamm | Off. Marcus |
| Dana Jay | Gangmember (Omars Crew) Camera Man |
| Jim Jones | Man on Street |
| Aubrohn King | Reporter |
| Brian E. McLarney | Off. Brian McLarney |
| Neal McNeil | Bartender |
| Jason Moffett | Off. Tony |
| Karl Otter | District Commander |
| Kwame Patterson | 'Monk' Metcalf |
| Devin Rumer | Corpse |