Mark Harmon NCIS Special Agent Leroy Jethro Gibbs Actor, Executive Producer Sean Murray NCIS Special Agent Timothy McGee Actor Emily Wickersham NCIS Special Agent Eleanor "Ellie" Bishop Actor Wilmer Valderrama NCIS Special Agent Nicholas "Nick" Torres Actor Maria Bello Special Agent Jacqueline "Jack" Sloane Actor Brian Dietzen Dr. Jimmy Palmer Actor Diona Reasonover Forensic Scientist Kasie Hines Actor Rocky Carroll NCIS Director Leon Vance Actor David McCallum Dr. Donald "Ducky" Mallard Actor Joe Spano Tobias "T.C." Fornell Guest Star Pam Dawber Marcie Warren Guest Star Margo Harshman Delilah Fielding Guest Star Katrina Law NCIS REACT Special Agent Jessica Knight Guest Star Victoria Platt NCIS Special Agent Veronica "Ronnie" Tyler Guest Star Juliette Angelo Emily Fornell Guest Star Nick Boraine Merriweather, Man Guest Star Anna Grace Barlow Karen Guest Star Connie Jackson Elaine Guest Star Isiah Adams Shift Manager Chad Guest Star Sandra Cevallos-Campanella Judge Monic Perez 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, Writer Donald P. Bellisario Executive Producer Brendan Fehily Writer Marco Schnabel Writer Margaret Rose Lester Writer Christopher J. Walid Writer Diana Valentine Director David J. North Writer Michael Zinberg Director James Whitmore Jr. Director Terrence O'Hara Director Tawnia McKiernan Director