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 Pam Dawber Marcie Warren Guest Star John Hensley Phil Hanover Guest Star Valarie Pettiford Sonia Eberhart Guest Star Wayne Charles Baker Tunu Alonak Guest Star Erik Passoja FBI Deputy Director Wayne Sweeney Guest Star Nikki McCauley Melanie Stafford Guest Star Karina Noelle Castillo FBI Agent Ramirez Guest Star Kimberly Christian Nina Bradshaw 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 Donald P. Bellisario Executive Producer David North Writer Brendan Fehily Writer Terrence O'Hara Director