Thomas Mark Harmon is an American actor, producer, director, voice actor and former football quarterback. He is best known for playing the lead role of Leroy Jethro Gibbs in NCIS. He also has appeared in a wide variety of roles since the early 1970s. Initially a college football player, his role on St. Elsewhere led to his being named "Sexiest Man Alive" by People in 1986. After spending the majority of the 1990s as a character actor, he played Secret Service special agent Simon Donovan in The West Wing, receiving a 2002 Emmy Award nomination for his acting in a four-episode story arc.Harmon's character of NCIS special agent Leroy Jethro Gibbs was introduced in a guest starring role in two episodes of JAG. Since 2003, Harmon has starred in NCIS as the same character.