Martin Sheen President Josiah "Jed" Bartlet Actor John Spencer Chief of Staff Leo McGarry Actor Rob Lowe Sam Seaborn Actor Bradley Whitford Dep. Chief of Staff Josh Lyman Actor Richard Schiff Communications Dir. Toby Ziegler Actor Allison Janney Press Secretary Claudia Jean "C.J." Cregg Actor Moira Kelly Mandy Hampton Actor Dulé Hill Charlie Young Actor Janel Moloney Donna Moss Actor Ray Baker Jonathan Lydell Guest Star Linda Gehringer Jennifer Lydell Guest Star Liza Weil Karen Larson Guest Star Dakin Matthews Simon Blye Guest Star Kathryn Joosten Mrs. Landingham Guest Star NiCole Robinson Margaret Guest Star Kim Webster Ginger Guest Star Suzy Nakamura Cathy Guest Star Timothy Busfield Danny Concannon Guest Star Kris Murphy Katie Witt Guest Star James Handy Rep. Joseph Bruno Guest Star Renee Estevez Nancy Guest Star Aaron Sorkin Executive Producer, Writer Thomas Schlamme Executive Producer John Wells Executive Producer Kristin Harms Producer Llewellyn Wells Producer Ken Olin Director