Mark Harmon
Mark Harmon portrayed the Special Agent for 18 seasons and left the show in the fourth episode of season 19.
Mark Harmon, one of the main cast of 'NCIS' may be returning to the show, but fans are still unsure…
Mark Harmon, who played the role of Leroy Jethro Gibbs bids goodbye to 'NCIS' after almost two decades as a…
Gettyimages | CBS Photo Archive Pauley Perrette and Mark Harmon starred together on “NCIS: Naval Criminal Investigative Service” until Perrette…