A Special Agent for the Naval Criminal Investigative Service and a former Marine Gunnery Sergeant, Gibbs (Mark Harmon) is an experienced criminal investigator and a highly-skilled interrogator. A born leader with great focus, Gibbs' often unorthodox approach and willingness to bend the rules always gets the job done.

Ducky (David McCallum), a medical examiner with the Naval Criminal Investigative Service, relishes everything he does. With a restless, inquisitive mind, he cannot let any problem go unsolved. As a result of constantly dealing with death, he has developed a keen, if somewhat dark sense of humor. A world traveler, he constantly recalls fascinating stories of his journeys.

Abby Sciuto (Pauley Perrette) is a "Jane of all trades" - from chemical and DNA processing to fingerprint and document analysis, she does it all. She has a Goth-chick attitude and tattoos to match, but underneath that, she takes her job as a lab tech seriously, and is a total pro.

As a former Baltimore Homicide Detective, Tony (Michael Weatherly) is tough and knows how to work the system. Young, brash and with plenty of comic relief, he's always trying to make ground on the more experienced Gibbs (Mark Harmon), to prove his mettle as an NCIS Special Agent.

With tremendous respect for Special Agent Gibbs (Mark Harmon), McGee (Sean Murray) is an intelligent agent with a specific talent for computers, but awkwardness in social situations.