| Dominic West | Off. James 'Jimmy' McNulty |
| Chris Bauer | Frank Sobotka |
| Paul Ben-Victor | Spiros 'Vondas' Vondopoulos |
| John Doman | Col. William A. Rawls |
| Idris Elba | Russell 'Stringer' Bell |
| Frankie Faison | Acting Commissioner Ervin H. Burrell |
| Lawrence Gilliard Jr. | D'Angelo Barksdale |
| 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 |
| Amy Ryan | Off. Beatrice 'Beadie' Russell |
| Sonja Sohn | Det. Shakima 'Kima' Greggs |
| Seth Gilliam | Sgt. Ellis Carver |
| Domenick Lombardozzi | Det. Thomas 'Herc' Hauk |
| Jim True-Frost | Det. Roland 'Prez' Pryzbylewski |
| James Ransone | Chester 'Ziggy' Sobotka |
| Pablo Schreiber | Nick Sobotka |
| Melanie Nicholls-King | Cheryl |
| Callie Thorne | Elena McNulty |
| Michael Kenneth Williams | Omar Little |
| Leo Fitzpatrick | Johnny Weeks |
| Robert Hogan | Louis Sobotka |
| Michael Kostroff | Maurice 'Maury' Levy |
| Kristin Proctor | Aimee |
| Al Brown | Maj. Stanislaus Valchek |
| Richard Burton | Sean 'Shamrock' McGinty |
| Lance Irwin | Maui |
| Delaney Williams | Sgt. Jay Landsman |
| Antonio D. Charity | CO Dwight Tilghman |
| Teddy Cañez | George 'Double G' Glekas |
| Elisabeth Noone | Joan Sobotka |
| Charley Scalies | Thomas 'Horseface' Pakusa |
| Jennifer Badger | Slavic Drowning Victim |
| John Bobby | Stevedore |
| Stanley Boyd | Cherry |
| Kelli R. Brown | Kimmy |
| Patrick Brown | Jury Foreman |
| Leslie Elliard | Off. Kevin Reynolds |
| Jeffrey Pratt Gordon | John 'Johnny Fifty' Spamanto |
| DeLon Howell | Inmate #1 |
| George Kardulias | Longshoreman |
| Joseph W. Lane | Corrections Officer Supervisor |
| David L. Marston | Long Shoreman |
| Vito Pietanza | FBI Agent |
| Jill Redding | Delores |
| Lizz Robbins | Pedestrian |