'NCIS' (promoted as 'Navy NCIS' in season one), aka 'Navy NCIS: Naval Criminal Investigative Service' or 'NCIS: Naval Criminal Investigative Service', is an American police procedural television series revolving around a fictional team of special agents from the Naval Criminal Investigative Service, which conducts criminal investigations involving the U.S. Navy and Marine Corps.The concept and characters were initially introduced in a two-part episode of the CBS series JAG (JAG episodes 8.20 and 8.21). The show, a spin-off from JAG, premiered on September 23, 2003 on CBS and, to date, has aired six full seasons, and has gone into syndicated reruns on USA Network and Sleuth. as of last year. Donald Bellisario, who created JAG, as well as the well-known series Magnum, P.I. and Quantum Leap, is co-creator and executive producer of NCIS. NCIS was originally referred to as "Navy NCIS"; however, "Navy" was later dropped from the title, as it was redundant. NCIS will return for a seventh... more