Which character suffers from multiple sclerosis?

Josiah Bartlet is the character who suffers from multiple sclerosis. The fictional President of the United States has relapsing-remitting MS, a form in which symptoms can flare and later improve or disappear for periods of time.

Bartlet has known about his diagnosis since 1992, before the events of the series. He keeps the condition secret during his presidential campaigns, creating one of the show's major political and ethical storylines. His secrecy becomes public during the second and third seasons, when questions arise about whether voters were misled about his health.

The storyline also involves his wife, Abigail Bartlet, a physician who secretly treats him with Betaseron. Bartlet eventually accepts congressional censure for failing to disclose the illness. The series emphasizes that MS is not automatically fatal and portrays symptoms such as fatigue, tremors, and periods of weakness. Toby Ziegler, Josh Lyman, and Leo McGarry do not have MS; Bartlet's illness is central to his character and presidency.