| 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 |
| Kathryn Erbe | Shirley Bellinger |
| Edie Falco | Officer Diane Whittlesey |
| Zeljko Ivanek | Governor James Devlin |
| 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 |
| Robert Clohessy | Officer Sean Murphy |
| Seth Gilliam | Officer Clayton Hughes |
| Kristin Rohde | Officer Claire Howell |
| Craig muMs Grant | Poet
(as muMs) |
| Tom Mardirosian | Agamemnon Busmalis |
| Larry Pine | Arnold Zelman |
| Anthony 'Treach' Criss | Malcolm 'Snake' Coyle
(as Treach) |
| J.D. Williams | Kenny 'Bricks' Wangler |
| Scott William Winters | Cyril O'Reily |
| Milo O'Shea | Dr. Frederick Garvey |
| Peter Appel | Lawrence Bailey |
| Dick Boccelli | Heinrick Schillinger |
| Patrick Breen | Robbie Gerth |
| Timothy L. Brown | Officer Jason Armstrong
(as Tim Brown) |
| Natascia Diaz | Margarita Ricardo
(as Natascia A. Diaz) |
| Carl DiMaggio | Officer Len Lopresti |
| Juan Carlos Hernández | Carlo Ricardo |
| Ernie Hudson Jr. | Hamid Khan |
| Jordan Lage | Richie Hanlon |
| Christopher Murphy | Arian Brother |
| Rockets Redglare | Barber |
| R.E. Rodgers | James Robson |
| Otto Sanchez | Chico Guerra |
| Philip Scozzarella | Officer Joseph Mineo
(as Philip V. Scozzarella) |
| Chuck Zito | Chucky Pancamo |
| Carlo Alban | Luis Ricardo
(uncredited) |
| Paula Garcés | Isabella
(uncredited) |
| Brett Gillen | Philip Featherstone
(uncredited) |
| Joey Napoli | Kitchen Helper
(uncredited) |
| John Perretti | Steve Pasquin
(uncredited) |
| Jamie Tirelli | Ferdinand Ricardo
(uncredited) |