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 Timothy Busfield Danny Concannon Actor Emily Procter Ainsley Hayes Actor Charley Lang Congressman Skinner Guest Star David Graf Colonel Chase Guest Star NiCole Robinson Margaret Guest Star Michael Tomlinson Republican Congressman Guest Star Gregg Daniel Steve Adamley Guest Star Aaron Sorkin Executive Producer, Writer Thomas Schlamme Executive Producer John Wells Executive Producer Kristin Harms Producer Llewellyn Wells Producer Paris Barclay Director