- Is one of five actors from the show Oz to be cast on Lost (the others being Harold Perrineau, Adewale Akinnuoye-Agbaje, Lance Reddick, and Ken Leung)
- Graduated from the London Academy of Music and Dramatic Art in 1980.
- He has been nominated for a Tony Award three times. He has also won the Drama Desk Award for Outstanding Actor in a Play.
- He has appeared in numerous TV shows including Homicide:Life on the Street, 24, ER, NYPD Blue, Cold Case and Law & Order.
- He won an Emmy Award for Best Supporting Actor far his role in Damages. One of the other actors nominated that year was Michael Emerson for his role as Ben Linus.
- He, Emerson Brooks (Tony Nagy) and Adetokumboh McCormack (Yemi) are the only actors to appear on Lost, 24, and Heroes.
- Portrayed Hally in the first performance of "Master Harold ... and the boys" at Yale Repertory Theatre on March 12, 1982.
- Played John Dickinson in the HBO miniseries John Adams.
- Appeared in a season 1 episode of True Blood, a show which has also featured Lost guest stars Michelle Forbes and William Sanderson.