Why did Gibbs left NCIS: Naval Criminal Investigative Service in season 19? Mark Harmon has been the face of NCIS as Special Agent In Charge Leroy Jethro Gibbs since its inception in 2003, so his departure changed the show’s dynamic from that point on. While Harmon continued to serve as an Executive Producer on the series despite Gibbs’ absence from the show, his character remained out of the picture. NCIS currently holds the honor as CBS’ longest-running scripted primetime series, following the lives and adventures of the federal special agents responsible for investigating felony crimes, preventing terrorism, and protecting secrets for the Navy and Marine Corps.
