The pilot for this series aired as a two-part episode of "JAG" (1995) in the spring of 2003. Two major changes were made for the series. A gimmick in which Ducky is shown talking to corpses - from the corpse's point of view - was dropped, and a character named Viv Blackadder (played by Robyn Lively) was replaced by the character played by Sasha Alexander.
One of the computer monitors used on the set is a 1600SW Flat Panel monitor built by Silicon Graphics in 1999 (hence the SGI abbreviation logo).
The t-shirts that Gibbs wears while working on the boat in the basement of his home are sent to Mark Harmon from law enforcement agencies around the country. He also occasionally wears a sweatshirt with the letters "NIS". This stands for "Naval Investigative Service", the predecessor of the NCIS. An agent with Gibbs' seniority would have begun his career working under that name.
DiNozzo's wealthy father cut him off from his inheritance when he was 12 years old. Michael Weatherly's father cut him off from his inheritance when he decided to pursue acting.
The sound heard at the beginning and end of each Act, when the scene goes to black and white is Donald P. Bellisario making that noise into a microphone. He wanted a unique way of bookending each act and took a microphone and went into a studio and made that sound into the microphone.
There is a picture of Donald P. Bellisario hanging on the "NCIS Most Wanted Wall"
At one point, Michael Weatherly's character states "I've got a better chance of hooking up with Jessica Alba than these guys do of infiltrating SeaLift.". Michael Weatherly was engaged for a time to Jessica Alba and starred opposite her on "Dark Angel" (2000).
The boat that Gibbs is building is an Amigo Kit from Glen-L.
The show was originally entitled "Navy NCIS". They dropped the "Navy", which was redundant because the "N" in "NCIS" stands for "Naval" referring to the Navy. "NCIS" stands for "Naval Criminal Investigative Service".
During the opening credits there is a note about what NCIS represents and it reads: The Naval Criminal Investigative Service (NCIS) is a worldwide federal law enforcement organization whose mission is to protect and serve the Navy and Marine Corps and their families.
The title of McGee's novel "Deep Six" is the name of an actual novel written by Clive Cussler.
In the opening credits, the aircraft carrier going under the bridge is a clip from the opening credits of The Presidio (1988), starring Mark Harmon as a San Francisco police inspector investigating a murder on the Presidio army base in San Francisco.
Timothy McGee uses the pseudonym Thom E Gemcity for his novel 'Deep Six'. Thom E Gemcity is an anagram for Timothy McGee.
The team frequently issues BOLOs for people - this stands for 'Be On Look Out'
Gibbs and his team frequently talk about "Local LEO's". LEO is short for Law Enforcement Officer(s).
MTAC stands for Multiple Threat Alert Center. It has also been defined as Multiple Threat Assesment Center.