| Kirk Acevedo | Miguel Alvarez |
| Adewale Akinnuoye-Agbaje | Simon Adebisi |
| Ernie Hudson | Warden Leo Glynn |
| Terry Kinney | Tim McManus |
| Rita Moreno | Sister Peter Marie Reimondo |
| Harold Perrineau | Augustus Hill |
| J.K. Simmons | Vern Schillinger |
| Lee Tergesen | Tobias Beecher |
| Eamonn Walker | Kareem Said |
| Dean Winters | Ryan O'Reily |
| Edie Falco | Officer Diane Whittlesey |
| Luis Guzmán | Raoul 'El Cid' Hernandez |
| Olek Krupa | Yuri Kosygin |
| Mark Margolis | Antonio Nappa |
| Christopher Meloni | Chris Keller |
| George Morfogen | Bob Rebadow |
| Luna Lauren Velez | Dr. Gloria Nathan
(as Lauren Vélez) |
| BD Wong | Father Ray Mukada |
| Granville Adams | Zahir Arif |
| Arija Bareikis | Tricia Ross |
| Philip Casnoff | Nikolai Stanislofsky |
| Robert Clohessy | Officer Sean Murphy |
| Seth Gilliam | Officer Clayton Hughes |
| Enid Graham | McManus's Attorney |
| Frederick Koehler | Andrew Schillinger
(as Fred Koehler) |
| Tom Mardirosian | Agamemnon Busmalis |
| Craig muMs Grant | Poet
(as muMs) |
| J.D. Williams | Kenny 'Bricks' Wangler |
| Scott William Winters | Cyril O'Reily |
| Lexington Alexander | Pierce
(as Malé Baby Alexander) |
| Timothy L. Brown | Officer Jason Armstrong
(as Tim Brown) |
| William Cote | Cudney
(as Will Cote) |
| Natascia Diaz | Ricardo
(as Natascia A. Diaz) |
| Carl DiMaggio | Lopresti |
| Tim Hopper | Donn |
| Ernie Hudson Jr. | Khan |
| Otto Sanchez | Chico Guerra |
| Nelson Vasquez | Rivera |
| Chuck Zito | Chucky Pancamo |
| Todd Etelson | Mario Seggio |
| Robert Lin | |
| Douglas Crosby | Officer D'Agnasti
(uncredited) |
| Brett Gillen | Philip Featherstone
(uncredited) |
| Juan Carlos Hernández | Carlo Ricardo
(uncredited) |