Mark Harmon decided to leave NCIS to keep his acting career "fresh". Gibbs was replaced by FBI agent Alden Parker in NCIS season 19. Gibbs's final episode was emotional as he reflects on his ...

The NCIS: Origins showrunners know what hearing Mark Harmon‘s voice as Gibbs, narrating the prequel, means to fans, and so chances are they’ll continue to hear it through the series’ run ...

Mark Harmon played Leroy Jethro Gibbs for years on "NCIS," and now Austin Stowell has taken on the role for "NCIS: Origins." But how old is Gibbs in both shows?