Mark Harmon is an American actor and producer, best known for his role as Special Agent Leroy Jethro Gibbs on the long-running television series NCIS. Born on September 2, 1951, in Burbank, California, he initially pursued a career in sports before transitioning to acting in the late 1970s. In addition to his work on NCIS, Harmon has appeared in various films and television shows, including St. Elsewhere and The Deliberate Stranger. He has received several awards for his performances and is recognized for his contributions to the entertainment industry.