| Kirk Acevedo | Miguel Alvarez |
| 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 |
| Betty Buckley | Suzanne Fitzgerald
(as Betty Lynn Buckley) |
| Anthony Chisholm | Burr Redding |
| Christopher Meloni | Chris Keller |
| George Morfogen | Bob Rebadow |
| Luna Lauren Velez | Dr. Gloria Nathan
(as Lauren Vélez) |
| Scott William Winters | Cyril O'Reily |
| BD Wong | Father Ray Mukada |
| Michael Wright | Omar White |
| Granville Adams | Zahir Arif |
| Robert Clohessy | Officer Sean Murphy |
| Mike Doyle | Adam Guenzel |
| Toni Lewis | Alicia Hinden |
| Eddie Malavarca | Peter Schibetta |
| Tom Mardirosian | Agamemnon Busmalis |
| Craig muMs Grant | Poet
(as muMs) |
| Pepa | Officer Andrea Phelan |
| Sandra Purpuro | Katherine McClain |
| Kristin Rohde | Officer Claire Howell |
| David Zayas | Enrique Morales |
| Chuck Zito | Chucky Pancamo |
| Jerome Preston Bates | Officer Travis Smith |
| Timothy L. Brown | Officer Jason Armstrong |
| Antoni Corone | Frank 'The Fixer' Urbano
(as Antoni Cornacchione) |
| M.G. Gong | #01J813 Jia Kenmin
(as Michael Delmare) |
| Carl DiMaggio | Officer Len Lopresti |
| Mtume Gant | Reggie Rawls |
| Chris Gardner | Ahmad Lalar |
| Nelson Lee | Li Chen |
| Carlos Leon | #98M232 Carlos Martinez |
| John Lurie | #97P528 Greg Penders |
| Ellen McElduff | Eleanor O'Connor |
| Andy Powers | #02W562 Franklin Winthrop |
| Christopher Rivera | Jaime Velez |
| Blake Robbins | Officer Dave Brass |
| R.E. Rodgers | James Robson |
| Otto Sanchez | Chico Guerra |
| Joel West | #99S917 Glen Shupe |
| Emmanuel Yarborough | #02B821 Clarence Seroy
(as Emanuel Yarbrough) |
| Whitney Allen | Miss Sally |
| Mike Arotsky | Max Sands |
| John Paul Cooney | Inmate 'The Kid'+ |
| Todd Etelson | Mario Seggio |
| Steven Johnson | Prisoner |
| Mam Smith | Lulu |
| Steven Wishnoff | Tony Masters |
| Frank Bonsangue | Sicilian Crew
(uncredited) |