Throughout its massive run on network TV, NCIS has garnered a long list of defining moments. While NCIS is a procedural TV show that focuses on the Naval Criminal Investigative Service, decades of NCIS characters are at the heart of the series, and their stories serve as milestones of the franchise’s journey. The series’ ability to create genuinely shocking moments while ushering new personalities in and out of the NCIS story makes it tick, from Sasha Alexander’s Kate Todd to Mark Harmon’s Leroy Jethro Gibbs.
The team’s NCIS season 22 roster — Katrina Law’s Jessica Knight, Gary Cole’s Alden Parker, Wilmer Valderrama’s Nick Torres — could take over the TV series because their predecessors were sent off with intention and purpose, allowing audiences to justify a new configuration of special agents. Many of NCIS’ defining moments are those where characters’ positions are in flux, causing a collective processing of the team and honest conversations about change, the backbone of the series’ longevity. The fluid rotation of familiar faces defines the series, enabling it to have a lasting impact.
10. Ari Kills Kate Todd
NCIS Season 2, Episode 23, “Twilight”
One of the overall story’s most pivotal moments is Kate’s shocking death in NCIS season 2. Kate is targeted by Ari Haswari (Rudolf Martin), a rogue Mossad double agent who holds Kate, Ducky (David McCallum), and Gerald (Pancho Demmings) hostage in NCIS season 1. After their initial encounter, Ari orchestrates several run-ins with Kate, tormenting her while exuding charm and refusing to admit he’s the bad guy.
At the end of season 2, just when it looks like Ari will shoot Gibbs, he redirects and kills Kate while she stands on a rooftop with her NCIS partners. Ari delivers a bullet to Kate’s forehead, instantly killing her and leaving viewers stunned. Alexander wanted to leave the series due to its demanding production schedule, and rather than give Kate a lackluster exit, NCIS established that no character was safe.
Her death and the storyline of Ari Haswari skillfully usher in Cote de Pablo’s Ziva David — Kate’s replacement. Ziva could have been a guest character appearing in a few episodes and never seen again. Instead, NCIS wove Ziva’s story into Kate Todd’s exit as Ari’s half-sister who ultimately delivers the fatal blow to him that redeems Kate’s death, shooting the most important NCIS antagonist in Gibbs’ basement to protect the Agent-in-Charge.
9. NCIS Reveals Leroy Jethro Gibbs’ Past
NCIS Season 3, Episodes 23 & 24, “Hiatus Part I” & “Hiatus Part II”
In NCIS season 3, the series reveals critical elements of the Marine’s past when Leroy Jethro Gibbs is in a coma in the “Hiatus” double episode. After experiencing an explosion aboard a Navy ship, Gibbs is unresponsive in the hospital. The team worries for their fearless leader’s life as Gibbs remains unconscious. Details of his life and experiences then begin to come together, adding a new layer of complexity to Harmon’s brash supervisory character.
Revealing what happened to Gibbs’ wife and daughter in NCIS changed the scout sniper’s entire story, leaving an indelible impact on the series and setting up the NCIS: Origins prequel.
In “Hiatus Part II,” Jenny Shepard (Lauren Holly) reveals that Gibbs had a wife and child, Kelly and Shannon, who he lost after a horrific murder. Gibbs’ family agreed to testify against a drug dealer named Pedro Hernandez, who killed Shannon and Kelly’s bodyguard while he was driving, with the mother and daughter dying from injuries sustained in the accident. Revealing what happened to Gibbs’ wife and daughter in NCIS changed the scout snipe’s entire story, leaving an indelible impact on the series and setting up the NCIS: Origins prequel.
8. The Major Case Response Team Loses Director Jenny Shepard
NCIS Season 5, Episodes 18 & 19, “Judgment Day Part I” & “Judgment Day Part II”
In NCIS season 5, the Major Case Response Team (MCRT) loses its director, Jennifer Shepard. Jenny is an empathetic leader who works well with the team, but instances from the director’s past haunt the character. In NCIS season 5, episode 18, “Judgment Day Part I,” Jennifer dies when she is out outnumbered 5-to-1 in a shootout that takes place in an unknown diner in the Mojave Desert while she is in California for a funeral related to her assassination.
This Forgotten NCIS Character Deserved So Much Better, 16 Years After Their Death
Jenny’s death is a defining moment of the series because it leads to a significant shift in power. Rocky Carroll’s Leon Vance character steps in as temporary NCIS director in season 5 while Jenny is hunting La Grenouille, and he officially takes Jher place in season 6 after her death. Vance joining the series was directly related to a link between Rocky Carroll and Mark Harmon before NCIS. The actors were on the CBS medical drama Chicago Hope before Harmon joined the police procedural in 2003.
7. Assassins Kill Eli David & Jackie Vance
NCIS Season 10, Episode 11, “Shabbat Shalom”
In “Shabbat Shalom,” hitmen hired by Ilan Bodnar (Oded Fehr) execute an assassination on Mossad Director Eli David (Michael Nouri) and kill Leon Vance’s wife, Jackie Vance (Paula Newsome). Jackie and her husband are dining with Ziva and her father, and Ziva steps outside to talk to Gibbs. She hears gunshots from inside the house and races after the hitman.
The deaths of Jackie and Eli remind the audience that NCIS agents and their families are always in danger.
When she returns, Gibbs and Tony have arrived, and when Ziva inspects the crime scene, she finds her father fatally wounded. Ziva cries out “Abba,” meaning father, and rushes to the director’s side. Ziva crying, cradling her father’s body in the corner, is a haunting, defining moment for the series. The deaths of Jackie and Eli remind the audience that NCIS agents and their families — especially someone like Eli David — are always in danger.
6. Ziva Exits NCIS
NCIS Season 11, Episode 2, “Past, Present, And Future”
In season 11, Cote de Pablo exited NCIS, and the series bid farewell to her character. Ziva has a robust stint with the MCRT, working with Gibbs’ team from NCIS seasons 3 to 11. Ziva’s exit in “Past, Present, And Future” is memorable because, after years of a will they/won’t they romance, Ziva and Tony share a kiss before Ziva boards a plane. The moment sets up an epic romance storyline for the couple, even though it was the last time they were on-screen together in NCIS.
Ziva’s NCIS departure is significant because she leaves a massive gap in the team. Tony is close to Ziva, but so are Gibbs, Abby (Pauley Perrette), and McGee (Sean Murray). Her exit rocks the team as they grapple with her permanent absence, barring others from using her desk. While Emily Wickersham replaced Ziva as Eleanor Bishop, there was a massive Ziva-shaped hole in the MCRT, which set up Tony’s departure a few years later.
5. Tony Learns He Has A Daughter
NCIS Season 13, Episode 24, “Family First”
The season 13 finale also defines the story with Michael Weatherly’s NCIS exit as Tony DiNozzo. Tony learns that Ziva’s family has been attacked and that his former partner is gone. Mossad Director Orli Elbaz (Marina Sirtis) arrives at the Navy Yard to tell Tony personally that he has a daughter named Tali. The storyline was a huge shock and a beautiful send-off for Weatherly’s character.
Elbaz explains that Ziva assured her Tony is Tali’s father and delivers their child to NCIS for Tony to raise. Feeling the burden of grief and the responsibility of his new role as a parent, Tony decides to step out of the line of fire to care for Tali. He plans to move to Paris and bids the team farewell, making a lasting mark on the series as NCIS bids farewell to one of the original MCRT members from the NCIS pilot.
4. Ducky Scales Back On His ME Duties
NCIS Season 15, Episode 3, “Exit Strategy”
When Ducky scales back his Medical Examiner duties in NCIS season 15, the entire team feels it, leaving a mark on the franchise. Ducky has a worthy replacement, Brian Dietzen’s Jimmy Palmer. That said, his successor has trouble with the reality of Dr. Mallard’s new opportunities in “Exit Strategy.” While Ducky’s arc in the episode initially looks like it could be the character’s exit, it simply sets him up to step back from his ME roles. McCallum carries on with the series as NCIS Historian.
When Ducky takes another step back in NCIS season 19, episode 5, “Face the Strange,” Jimmy has another adverse reaction. Dr. Palmer recounts how everyone is leaving him, but Ducky takes the time to remind him that change is the essence of life. It’s one of Ducky’s best quotes in NCIS and spoke perfectly to his permanent exit from the series a few years later when David McCallum passed away at 90.
3. Abby Sciuto Moves To London
NCIS Season 15, Episode 22, “Two Steps Back”
Another massive moment for NCIS was the exit of the team’s Chief Forensic Scientist, Abby Sciuto. After Abby and Clayton Reeves (Duane Henry) are robbed at gunpoint in the street, they suffer brutal gunshot wounds, killing Reeves and leaving Abby in the hospital. As it turns out, the whole thing was a deliberate attack on the scientist, planned by Robert King (Peter Jason) to assassinate Abby.
Deeply affected by the death of Reeves, Abby moves to London to develop a charity connected to her former colleague. Perrettess NCIS exit was monumental for the series for several reasons. First, Perrette was with NCIS for 16 years, and her absence is as significant as Gibbs or Ziva. “Two Steps Back” and the events leading to the episode also define NCIS because it calls to mind Mark Harmon and Pauley Perrette’s NCIS feud, which greatly influenced her choice to leave the series.
2. MCRT Learns Ziva Is Alive
NCIS Season 16, Episode 24, “Daughters”
After her reported death, one of the most overwhelming moments of NCIS so far was the news that Ziva David was alive. After the attack on her family’s farmhouse, Ziva faked her own death. In the NCIS season 16 finale, the agent appears in Gibbs’ basement after it is strongly implied that she is alive in NCIS season 16, episode 13, “She.”
Ziva’s survival changed everything for NCIS. It redeems one of its saddest storylines, Tony’s series departure. After Ziva clears up her affairs and returns for a few outings in season 17, the former Mossad agent departs the series again, leaving to reunite with her daughter and the father of her child. Ziva’s return to NCIS set up the Tony and Ziva NCIS spinoff story, which will be available to stream on Paramount+ sometime next year.
1. Leroy Jethro Gibbs Retires
NCIS Season 19, Episode 4, “Great Wide Open”
Yet the most defining moment of the series’ later seasons is the retirement of central NCIS character Leroy Jethro Gibbs. After playing the character for nearly two decades of his life Harmon exited NCIS in season 19. After a case takes Gibbs and McGee to Alaska, the Agent-in-Charge decides to retire and stay in Naktok Bay.
Mark Harmon is an executive producer for NCIS and NCIS: Origins.
Impressively, one of the most fluid and skillfully executed transitions in NCIS is when Gary Cole’s Alden Parker replaces Gibbs. The laid-back FBI agent completely contrasts with Harmon’s reserved, silent type. The difference in personality creates minimal basis for comparison, and Cole has been a fantastic replacement. Additionally, while Harmonss story ceased to continue in the original, NCIS explores his backstory in a prequel about Gibbs’ start at NIS, the NCIS: Origins spinoff story.
