In seasons one and two, it is revealed that while with the CIA, Callen worked alongside recurring NCIS character Trent Kort (David Dayan Fisher), and was partnered with Tracy Rosetti (Marisol Nichols).

In addition to English, Callen is fluent in at least six other languages: Spanish, Polish, Russian, German (which is claimed to be Austrian, and is usually completely butchered), Italian (with a Northern accent), and French.

Kensi joined the Naval Criminal Investigative Service in August 2006, according to her NCIS agent biography form from "Black Market" after having graduated from Cornell University with a BA in Politics and International Studies.

Donald Blye died trying to protect an American journalist named Brad Stevens who was about to expose Peter Clairemont (chief of the Oscar-Sierra unit) who had killed a civilian while intoxicated.

In season nine, Kensi and Deeks are officially engaged and begin planning for the wedding while at the same time meet executive assistant director, Shay Mosley who replaces Owen Granger.

When her agents were in serious danger in the episodes "Ambush" and "Found", she used her considerable political capital and aforementioned contacts to pull out all the stops in rescuing them (such as convincing SecAF to authorize a F-22 Raptor fly-over of the militia camp).

)[19] In the thirteenth season premiere, Hetty left OSP to embark on a long-term assignment in Syria and following her departure, retired Navy Admiral Hollace Kilbride has replaced her as the Operations Manager.

[31][32] Much of his career is vague due to the highly classified nature of most of his missions, although it has been mentioned that he served in Bosnia[31] (Yugoslav Wars),[33] Chad (Pan Sahel Initiative),[34] Iraq[31] and Afghanistan[35][36] and was stationed at the Naval Special Warfare Center in Coronado at some point.

Although usually reticent about his service, Sam has hinted several times about how his experiences overseas have affected him: he mentions about getting help in "Field of Fire" when interviewing a homeless veteran who was distrustful of him[36] and admits to Nate Getz in the episode "Impact" of his worries that he would one day lose himself.

Sam was trapped inside their boat shed and beaten up by Habib's men with Callen, Kensi and Deeks launching a rescue operation which was successful, resulting in the deaths of the terrorists.

Callen helps him through his grief and by Season 10, when he suspects Sam has an interest in fellow NCIS Agent Nicole Dechamps (Marsha Thomason), he tells him Michelle would want him to be happy and move on with his life.

[44] Eric Bartholomew Beale III (portrayed by Barrett Foa) is an NCIS technical operator and intelligence analyst stationed in Los Angeles with the Office of Special Projects.

He is a geek and, like Detective Marty Deeks (Eric Christian Olsen), enjoys surfing (twice standing his surfboard too closely to Hetty's car) and internet social networks.

Martin Atticus "Marty" Deeks (Eric Christian Olsen) is a member of the Los Angeles Police Department who went to law school and passed the California Bar Examination and was previously a Public Defender.

They attempt to keep their romance secret until the rest of the team reveal their awareness of their relationship in "Fighting Shadows" when Deeks and Kensi are forced to partner with Callen and Sam respectively.

Deeks begins to face serious pressure when he discovers his job has been terminated permanently and that he has been furloughed by the LAPD until their budget issues surrounding the reform are resolved, and learns that he cannot attend FLETC due to being too old at this point, forcing him to leave NCIS for good.

This is often up for debate though, since in the season three episode "Patriot Acts", Nell flirts with Nate (who immediately picks up on her true intentions) in order to get Eric's attention and in "Greed", she avoids the subject of who sent her flowers.

In the episode "War Cries" Nell defends herself in the boat shed with a knife pulled from her boot, after the suspect gets her weapon away from her, dealing enough damage to send him to the hospital while she receives only a small cut above the right eye causing Granger to quip, "Not bad for an analyst".

In the season three finale, he helped the team tackle the case of "The Chameleon", a serial killer responsible for the deaths of Agent Mike Renko and former Operations Manager Lauren Hunter.

Granger was heavily involved in the effort to apprehend Isaak Sidorov and the Cold War-era nuclear weapons he stole, proving a strong support to the team when he learns that the only agent to have been able to maintain a deep cover with him was Michelle, Sam Hanna's wife.

In the season 8 episode "Crazy Train", Granger reveals that he is dying from a form of cancer which he admits could have been caused by any of his actions, including being exposed to Agent Orange from while he was in the Triangle prior to being extracted from Laos.

In Granger's written good-bye, he expresses his thanks to Hetty, explaining that he has had enough bullets and hospitals for one lifetime and has decided to put his last affairs in order, effectively parting ways with the team without subjecting them to his impending death from cancer.

Namazi first appears halfway through in season 10 in the two-parter "Smokescreen", where she helps the team pursue a terrorist cell responsible for bombing a movie theater in the first of a series of planned attacks on Los Angeles.

Tony is the Sr. Field Agent and second in command of the Major Case Response team in Washington D.C. since before the series premier to Weatherly's departure from the show at the end of NCIS's 13th season.

DEA agent Talia Del Campo (portrayed by Mercedes Mason) first appears in Season 5 episode "Fish Out of Water", where she is introduced as an undercover investigating a case after a witness and civilian are killed.

Mowahd[55] (variant spelling Mowadh[56]) "Moe" Dusa (portrayed by Ronald Auguste) is a Sudanese national who was brought to the US as a child by Sam Hanna (who was still serving as a Navy SEAL at the time).

Chegwidden (portrayed by John M. Jackson) is the retired Judge Advocate General of the United States Navy, now in private practice in Washington, D.C., and an old friend and colleague of NCIS Operations Manager Hetty Lange.

Louis Ochoa (portrayed by Esai Morales) is the NCIS Deputy Director who takes control of the Los Angeles office in Hetty's absence, and after the departure of Shay Mosley.

She was a former USMC Lieutenant working as a military police officer, and almost two decades earlier had investigated then-USMC Gunnery Sergeant Leroy Jethro Gibbs' role in the murder of Mexican drug lord Pedro Hernandez.

Due to the past investigation, their relationship was volatile until the OSP's operational psychologist Nate Getz revealed to Gibbs that Macy had been protecting him for eighteen years by covering up the evidence.