Mark Harmon NCIS Special Agent Leroy Jethro Gibbs Actor, Executive Producer Pauley Perrette Forensic Specialist Abby Sciuto Actor Sean Murray NCIS Special Agent Timothy McGee Actor Wilmer Valderrama NCIS Special Agent Nicholas "Nick" Torres Actor Jennifer Esposito NCIS Special Agent Alexandra "Alex" Quinn Actor Emily Wickersham NCIS Probationary Agent Eleanor "Ellie" Bishop Actor Brian Dietzen Dr. Jimmy Palmer Actor Duane Henry MI6 Officer Clayton Reeves Actor Rocky Carroll NCIS Director Leon Vance Actor David McCallum Dr. Donald "Ducky" Mallard Actor Margo Harshman Delilah Fielding Guest Star Mailon Rivera Cmdr. Bitterman Guest Star Nick Clifford Navy Petty Officer 1st Class Reed Haring Guest Star Tom Williamson Ensign Stoddard Guest Star Christina Ferraro Navy Chief Mary Choi Guest Star Robinne Lee Doctor Guest Star Alex Blue Davis Vernon Palumbo Guest Star Madeline Bertani Regina Jones Guest Star Chas. Floyd Johnson Executive Producer Mark Horowitz Executive Producer Frank Cardea Executive Producer George Schenck Executive Producer Steven D. Binder Executive Producer Scott Williams Executive Producer, Writer Donald P. Bellisario Executive Producer Jennifer Corbett Writer James Whitmore Jr. Director