Rob Lowe Sam Seaborn Actor Martin Sheen President Josiah "Jed" Bartlet Actor Bradley Whitford Dep. Chief of Staff Josh Lyman Actor John Spencer Chief of Staff Leo McGarry Actor Richard Schiff Communications Dir. Toby Ziegler Actor Allison Janney Press Secretary Claudia Jean "C.J." Cregg Actor Dulé Hill Charlie Young Actor Janel Moloney Donna Moss Actor Stockard Channing Abigail "Abbey" Bartlet Actor John Amos Percy Fitzwallace Actor Lily Tomlin Deborah Fiderer Actor Adam Arkin Dr. Stanley Keyworth Guest Star Mary-Louise Parker Amy Gardner Guest Star Mark Harmon Agent Simon Donovan Guest Star James Brolin Governor Robert Ritchie Guest Star Kurt Fuller Situation Room Civilian Advisor Guest Star Michael O'Neill Secret Service Agent Ron Butterfield Guest Star David Huddleston Senator Max Lobell Guest Star Armin Shimerman Richard III Guest Star NiCole Robinson Margaret Guest Star Renee Estevez Nancy Guest Star Andrew McFarlane Anthony Marcus Guest Star William Thomas Jr. Situation Room Advisor David Guest Star Glenn Morshower Mike Chysler Guest Star Thomas Kopache Assistant Secretary of State Bob Slatterly Guest Star Kris Murphy Katie Witt Guest Star Aaron Sorkin Executive Producer Thomas Schlamme Executive Producer John Wells Executive Producer Paul Redford Producer Michael Hissrich Producer Kristin Harms Producer Llewellyn Wells Producer Alex Graves Director