8x10 autographed photo of Mark Harmon, star of NCIS along with Call Sheet (received by cast members each day advising them when/where filming will be next day along with extras) Since 2003, Harmon has starred as NCIS Special Agent Leroy Jethro Gibbs in CBS' drama television show NCIS, 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.