Mark Harmon NCIS Special Agent Leroy Jethro Gibbs Actor, Executive Producer Sean Murray NCIS Special Agent Timothy McGee Actor Wilmer Valderrama NCIS Special Agent Nicholas "Nick" Torres Actor Brian Dietzen Dr. Jimmy Palmer Actor Diona Reasonover Forensic Scientist Kasie Hines Actor Katrina Law NCIS Special Agent Jessica Knight Actor Rocky Carroll NCIS Director Leon Vance Actor David McCallum Dr. Donald "Ducky" Mallard Actor Gary Cole FBI Special Agent Alden Parker Actor Jared Gertner Royman Beesbo Guest Star Eden Malyn Lillian Beck Guest Star Dennice Cisneros Disposal Technician a.k.a. Helen Guest Star Freedom Bridgewater Sergeant Joe Guest Star Rob James Guard Guest Star Aidan Merwarth Uptown Guest Star Najee Muhammad Street Guest Star Rif Hutton Marine General Phillip Braxton Guest Star Megan Gallagher Under Secretary of the Navy Jennifer Leo Guest Star Christian Valderrama Clubby Guest Star Chas. Floyd Johnson Executive Producer Mark Horowitz Executive Producer Frank Cardea Executive Producer George Schenck Executive Producer Steven D. Binder Executive Producer, Writer Scott Williams Executive Producer Donald P. Bellisario Executive Producer Diana Valentine Director