Thomas Mark Harmon is a renowned American actor, producer, and director. He rose to prominence in the 1980s, earning an Emmy nomination for his role in the TV movie The Deliberate Stranger. Harmon is best known for his iconic portrayal of Special Agent Leroy Jethro Gibbs in the long-running CBS drama NCIS, a role he played for over 18 seasons. Before his acting career, Harmon was a successful college football quarterback for the UCLA Bruins.