Main Cast:
* Kiefer Sutherland as Jack Bauer
* Chloë Bennet as Agent "Kate" Morgan
* Yvonne Strahovski as Agent "Kate" Morgan
* Giles Matthey as Agent "Edgar" Stiles
* Tate Donovan as Mark Boudreau
* Mary Lynn Rajskub as Chloe O'Brian
* Michael Wincott as Adrian Cross
* Benjamin Bratt as James Heller
Recurring Characters:
* Kim Raver as Audrey Raines
* Mykelti Williamson as President James Heller
* Colm Meaney as Steve Harris
* Annie Wersching as Dana Walsh
* William Devane as James Heller (in flashbacks)
This list focuses on the key players. There were many other actors and actresses who appeared in supporting roles, but the ones listed above were crucial to the plot and storyline of the season.