Muse Watson - Charles 'The Old Head' Westmorland (18/22 episodes).Frank Grillo - Nick Savrinn (18/22 episodes).Phillip Edward Van Lear - Corrections Officer Louis Patterson (19/22 episodes).Stacy Keach - Warden Henry Pope (20/22 episodes).Rockmond Dunbar - Benjamin Miles 'C-Note' Franklin (16/22 episodes).Robert Knepper - Theodore 'T-Bag' Bagwell (19/22 episodes).Paul Adelstein - Secret Service Special Agent Paul Kellerman (19/22 episodes).Sarah Wayne Callies - Doctor Sara Tancredi (22/22 episodes).Wade Williams - Captain Brad Bellick (22/22 episodes).Peter Stormare* - John Abruzzi (17/22 episodes).Marshall Allman - Lincoln 'LJ' Burrows Jr (11/22 episodes).Amaury Nolasco - Fernando Sucre (22/22 episodes).Robin Tunney - Veronica Donovan (22/22 episodes).Wentworth Miller - Michael Scofield (22/22 episodes).Dominic Purcell - Lincoln Burrows (22/22 episodes).
Paul Adelstein and Robert Knepper were credited as guest stars before episode 3 Peter Stormare was credited as a guest star after episode 13 and Rockmond Dunbar was credited as a guest star before episode 14.
