NCIS premiered on CBS, marking the beginning of the popular naval crime procedural series.
NCIS celebrated its ten-year milestone, highlighting its success and longevity in prime time television.
Mark Harmon, lead actor of NCIS, officially became an executive producer starting Season 10, taking a larger role behind the scenes.
NCIS aired its 300th episode, a significant achievement showcasing the show's enduring popularity.
Pauley Perrette, who portrayed Abby Sciuto, left NCIS after Season 15, ending a significant era for the series.
NCIS surpassed the 400-episode mark, becoming one of the longest-running scripted non-animated series in US television history.
The Naval Criminal Investigative Service is established as the primary law enforcement agency of the U.S. Navy and Marine Corps.
Leroy Jethro Gibbs joins NCIS as a special agent, beginning his career in naval criminal investigations.
Gibbs forms the core NCIS investigative team in Washington D.C., including key members like Tony DiNozzo, Kate Todd, and Abby Sciuto.
Special Agent Kate Todd is tragically killed by a sniper in an attack during an investigation, deeply affecting the team.
Former Mossad officer Ziva David joins the NCIS team as a special agent, bringing unique international experience.
Dr. Donald 'Ducky' Mallard begins his tenure as the NCIS medical examiner, becoming a vital team member.
Tony DiNozzo becomes the senior field agent under Gibbs, taking on leadership responsibilities during investigations.
Gibbs' mentor and friend Mike Franks is killed, which profoundly impacts Gibbs' personal and professional life.
Timothy McGee becomes a full-time NCIS special agent, specializing in cybercrime and technical investigations.
Gibbs steps down from his role as team leader due to personal reasons, leading to a temporary reorganization of the team.
Ziva's mother, Jenny Shepard, is appointed as the NCIS director, leading the agency during critical times.
Ziva leaves NCIS under complicated circumstances, affecting team dynamics.
Eleanor Bishop joins the NCIS team as a special agent, transitioning from the FBI to NCIS.
After a period away, Gibbs returns to lead the NCIS investigative team once again.
