The series revolves around a fictional team of special agents from the Naval Criminal Investigative Service (NCIS).

Donald P. Bellisario and Don McGill are co-creators and executive producers of the premiere member of the NCIS franchise.

The team, called the Major Case Response Team (MCRT) primarily responds to high-visibility crimes; NCIS is the main federal law enforcement agency of the United States Department of the Navy, investigating criminal activities (e.g. deaths, force protection, treason, etc.)

These JAG episodes introduced the characters of Jethro Gibbs, Anthony DiNozzo, Vivian Blackadder, Abby Sciuto, and Donald "Ducky" Mallard.

Michael Rainer in "A Weak Link", and John M. Jackson appeared as retired Rear Admiral A. J. Chegwidden in the season-10 episode "Damned If You Do".

"Legend" introduces Chris O'Donnell as G. Callen, LL Cool J as Sam Hanna, Daniela Ruah as Kensi Blye, and Barrett Foa as Eric Beale.

John M. Jackson has appeared on NCIS: Los Angeles as his JAG character Admiral A. J. Chegwidden, while this series has also crossed over with Hawaii Five-0 and Scorpion.

"Crescent City" introduces Scott Bakula as Dwayne Pride, Lucas Black as Christopher LaSalle, Zoe McLellan as Meredith Brody, and CCH Pounder as Loretta Wade.

Rocky Carroll recurs as Director Leon Vance, while NCIS series regulars Mark Harmon, Michael Weatherly, Pauley Perrette, Sean Murray, Emily Wickersham, Wilmer Valderrama, David McCallum, and Brian Dietzen have all appeared as their NCIS characters.

The decision to use this name was reportedly made by CBS, over the objections of Bellisario,[9] who preferred the old title because he felt it would: In 2011, NCIS was voted America's favorite television show in an online Harris poll.

[17] On January 8, 2025, it was announced that NCIS would suspend production due to the wildfires in the Southern California region, where the show is filmed.

[21] Due to a disagreement with series star Mark Harmon, Bellisario's duties as showrunner/head writer were to be given to long-time show collaborators, including co-executive producer Chas.

[24][25] NCIS airs on Network 10, 10 Bold, Fox Crime (formerly TV Hits and TV1) and Paramount+[26] in Australia,[27][28][29][30][31][32][33] Global (syndicated on sister channels Showcase and Lifetime) in Canada, TV3 and The Box in New Zealand, Seriale+ (premieres), TVN (free-TV premieres), TVN7 (reruns), AXN (reruns), (India) Fox Crime, Star World India (Pakistan) ARY Digital, ARY Zindagi, TVOne Pakistan and TV Puls (reruns) in Poland, Disney+ Hotstar and Rock Entertainment in Southeast Asia, Channel 5 in the United Kingdom, M6 in France, RTÉ2 in Ireland, Rai 2 in Italy, and Ion Television in USA.

In November 2008, it was reported that a first spin-off series set in Los Angeles would be introduced with a two-part backdoor pilot during the sixth season of NCIS.

[94] Linda Hunt and Adam Jamal Craig were added the cast as OSP Manager Henrietta Lange and Special Agent Dom Vail respectively.

[95] Craig, would not be returning for second season and was replaced by Eric Christian Olsen as Marty Deeks promoted to series regular.

However, discussions continued between CBS and Bellisario, and in January 2013 the dispute was settled outside of court a week before it was set to go to trial; the terms of the agreement were not disclosed but were described as being amicable.

[102][103][104] In September 2013, it was reported that a second spin-off series set in New Orleans would be introduced with a two-part backdoor pilot during the eleventh season of NCIS.

On February 16, 2021, it was reported that a spin-off set in Hawaii was in the works from NCIS: New Orleans executive producers Christopher Silber and Jan Nash.

[115] On April 23, 2021, it was announced that CBS had given the production a straight-to-series order to the spin-off, and intended to include the franchise's first female lead character.

[117][118][119] It also aired on CBS in the United States from November 14, 2023, as a result of the suspension of other NCIS productions due to the 2023 Hollywood labor disputes, and will be available for streaming in selected territories internationally on Paramount+.

[120][121] The cast is led by Olivia Swann and Todd Lasance, with Sean Sagar, Tuuli Narkle, Mavournee Hazel and William McInnes.

[122] On January 5, 2024, it was announced that a spin-off and prequel series based on Leroy Jethro Gibbs's early days as an NCIS agent was in the works.

[124] On February 28, 2024, it was announced that Paramount+ had ordered another spin-off of NCIS of 10 episodes focusing on Michael Weatherly and Cote de Pablo's characters Tony DiNozzo and Ziva David.