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 Robert Wagner Anthony Dinozzo Sr. Guest Star Richard Riehle Walt Osorio Guest Star Jessica Walter Judith McKnight Guest Star Todd Louiso Lyle Waznicki Guest Star Nick Jandl Michael Kettering Guest Star Steven Cox Taj Robinson Guest Star Austin Highsmith Garces Darlene Jones Guest Star Michael Broderick Navy Cmdr. James Shelty Guest Star Kristina Klebe Navy Lt. Cheryl Dombrowski Guest Star Hermie Castillo Zeke Guest Star Chas. Floyd Johnson Executive Producer Mark Horowitz Executive Producer, Director Frank Cardea Executive Producer George Schenck Executive Producer Steven D. Binder Executive Producer Scott Williams Executive Producer Donald P. Bellisario Executive Producer Brendan Fehily Writer