Mark Harmon
No TV would be complete without their leading man or lady, and Mark Harmon had no trouble leading the NCIS ship. He donned his hoodie and badge to become Supervisory Special Agent and Special Agent in Charge Leroy Jethro Gibbs from seasons one to 19. And while the former Marine sniper could always be found in the middle of the action, it's fair to say that he needed a lot of help along the way - and that's where his co-workers came in to play.
NCIS dominated a huge part of Mark Harmon's career, but it seems as though he's not ready to step away from it yet. He's still a star and executive producer of two spin-offs, including NCIS: New Orleans and NCIS: Origins.
Liza Lapira
Special Agent Michelle Lee, played by Liza Lapira, first made her way onto our screens in season four of NCIS. And while she started off as a strong asset to the team, her story took a turn when she became a mole in season six. In fact, she even kills multiple members of her team throughout the course of her espionage. She was then killed herself and her time on the show came to an end.
Although this was a huge storyline for Liza, it wasn't anything she wasn't used to. Over the course of her career, she has appeared in other big shows like The Equalizer and Grey's Anatomy. In 2024, she also took on a voice role in Inside Out 2.
David McCallum
For seasons one through 20, David McCallum stepped into the shoes of Dr. Donald "Ducky" Mallard in NCIS. The chief medical examiner and historian was hugely respected within his team - despite being a little eccentric. It was these eccentricities that put actor David McCallum on the map, but that's not to say that he wasn't famous before. In fact, this Scottish actor first rose to fame in The Man from U.N.C.L.E in the 1960s.
When Mark Harmon left NCIS in 2021, Callum decided to stay for the ride and continued to work on the show in a reduced capacity. Sadly, he passed away just two years later.
Sean Murray
Sean Murray proved to everyone that he was up to the task of being a big NCIS star. After making his mark as NCIS Senior Field Agent Timothy McGee in a recurring role in the first season, he impressed fans so much that he was bumped up to the main cast - and he's still starring in the show today. The cybersecurity and computer crime expert is regarded as one of the smartest on the team, too.
If you're still watching NCIS after Mark Harmon's departure, you'll know that Murray took over to become the show's lead character. Of course, this ruffled a few feathers - but he's generally been met with positive reviews.
Cote De Pablo
In a TV show largely dominated by men, Cote De Pablo offered some welcome female relief. The Chilean-born actress joined the show in season three as NCIS Special Agent Ziva David, and it's fair to say that she kept things interesting. From replacing the woman who her half-brother killed to being captured by the enemy in Somalia, there was never a dull episode when Ziva David was on the screen.
In real life, Cote decided that her time on NCIS should come to an end in season 16. But it seems as though she can't stay away from her life as Ziva, as it was announced in 2024 that she would reprise her role for the spin-off show NCIS: Tony & Ziva.
Joe Spano
Although he's arguably not one of the main characters in NCIS, Joe Spano still rose to popularity through his role as FBI Special Agent Tobias C. Fornell. He first made his mark in the very first episode, helping out - and sometimes hindering - the general day-to-day life of Leroy Gibbs. In season 15, Fornell also made a big career change when he decided to leave the FBI and become a private investigator.
Although Joe Spano will forever be known for his role in NCIS, his career hasn't depended on this show. He started acting in 1967 and has been in numerous TV shows and movies. He even voiced Chuck E. Cheese for six years.
Lauren Holly
Lauren Holly joined the NCIS cast as NCIS Director Jenny Shepard in season three. And while she was just a recurring character at first, she quickly won over the hearts of fans and was promoted to a main season regular from seasons four to five. However, her on-screen character struggled with her health and was later killed, which meant that we had to say goodbye to her. This was apparently Lauren's choice, though.
Lauren reportedly wanted to expand her acting horizons after NCIS, but she fell into a similar field as she later went on to take on a leading role in the political thriller drama, Designated Survivor.
Scottie Thompson
One thing you might not realize about Scottie Thompson is that her role on NCIS was one of her first. Although she had bagged a few small roles here and there, becoming Jeanne Benoit in season four was her first recurring gig. For this role, she served as the girlfriend of Tony DiNozzo and was later revealed as the daughter of the infamous arms dealer René Benoit. She quit after one season, though.
Although Scottie had plans to appear in bigger and better productions, things just didn't work out for her. So, she decided to return to her old role in NCIS in season 13.
Jennifer Esposito
Season 14 brought a few new changes for NCIS, one of which was the arrival of NCIS Special Agent Alexandra Quinn. Although her character left after just one season to look after her sick mother, she still made a big impact - and so did the actress Jennifer Esposito. And while NCIS fans know her as Alexandra, it's fair to say that this show wasn't her big break. She's been in so many other hits.
In fact, she was recently found taking on the role of CIA Deputy Director Susan Raynor in the hit television show The Boys, and she currently stars in Awkwafina Is Nora from Queens.
Emily Wickersham
Some of the biggest NCIS characters started off as guests of the show, and this was the case in season 11 when Emily Wickersham took on the role of NCIS Special Agent Eleanor Bishop. But she made such a good impression that she was promoted to the main cast for the next seven seasons. After all, fans couldn't get enough of her typical country looks mixed with her impressive brain and eye for data.
In 2021, Emily announced on Instagram that she would be leaving NCIS, and this came as a tough blow to fans. Especially as she hasn't booked any acting roles since.
Alicia Coppola
Although she's not related to the famous Coppola family, Alicia Coppola is still a popular and talented actress. She proved this when she took on the role of Lieutenant Commander Faith Coleman in NCIS in 2004. But eagle-eyed NCIS fans may also remember that she later appeared as FBI Agent Lisa Rand in five episodes of NCIS: Los Angeles. And while she didn't have a huge role in this franchise, it still set her up for success.
Since her time on the show, Alicia has appeared on many other TV shows, including Shameless, Blood & Treasure, Why Women Kill, and Generation. She definitely prefers TV to movies.
Jamie Lee Curtis
Jamie Lee Curtis is such a famous face in Hollywood that you might not even remember her time on NCIS. After all, she made a name for herself in the '70s and '80s as the Scream Queen. And it was during a lull in her career in 2012 that she was given the chance to star in NCIS as Dr. Samantha Ryan. Although the showrunners wanted Ryan to have a romantic relationship with Gibbs, Jamie didn't want to continue on the show.
Since then, she's gone from strength to strength to become a huge name in Hollywood - particularly in the movie world. At the time of writing, she has three movies in post-production, including Freakier Friday.
Pauley Perrette
NCIS fans will know that the show wouldn't have been the same without NCIS Forensic Specialist Abby Sciuto. This character graced our screens from season one all the way to season 15, and everyone seemed to love her alternative look, her big heart, and her loyalty and love for her team. Thankfully, Pauley Perrette was willing to play Abby for as long as she did - but there came a time when she decided that enough was enough.
Although Abby landed a few roles after NCIS, she decided to retire from acting in 2020. Sadly, she also suffered a stroke in 2021, so she now spends her days recuperating.
Michael Weatherly
True NCIS fans will know that this show hasn't been the same since Senior Field Agent Anthony DiNozzo said his goodbyes in season 13. And while he made a short cameo in season 21, this didn't fill the hole that this goofball personality left behind. After all, DiNozzo was slightly divisive in terms of his remarks and his actions, but at the end of the day he had a spark that couldn't be replicated.
Of course, we had Michael Weatherly to thank for that - but what's he up to now? Well, from 2016 to 2022, he starred as the lead in Bull, and he'll soon be starring in the NCIS spin-off, NCIS: Tony & Ziva.
Tamara Taylor
If you cast your mind back to 2005 NCIS, you might remember a woman by the name of Special Agent Cassie Yates. Although she only appeared in two episodes, she certainly made an impact - and fans definitely wanted more from her. But it seems as though Canadian actress Tamara Taylor couldn't commit to any more time on set, as she was quickly snapped up to play Dr. Camille Saroyan in Bones.
Tamara starred as Dr Camilla for 11 years before continuing her reign on television. She seems to love her crime shows, too, as she's also starred in Law & Order: Organized Crime.
Daniela Ruah
American-Portuguese actress Daniela Ruah first made her mark in Portuguese TV shows and movies, but her time to shine came in 2009 when she was offered the chance to play Special Agent Kensi Blye in NCIS: Los Angeles. This was a role that suited the beautiful actress perfectly, and fans fell in love with her on-screen presence and complicated storylines - mainly involving her relationship with LAPD-NCIS Liaison Marty Deeks.
All in all, Daniela appeared in 2 episodes of NCIS and 277 episodes of NCIS: Los Angeles, but she has been fairly busy ever since and continued to work on various different TV shows.
Brian Dietzen
In seasons one through five, Brian Dietzen was given the chance to take on the recurring role of Dr. Jimmy Palmer. He continued to play this nerdy character from seasons six to nine, but it wasn't until season ten that he became one of the leading characters. In fact, fans seemed to fall in love with his ramblings and the fact that his co-workers lovingly teased him on a regular basis.
For Brian Dietzen, becoming a bigger player in the NCIS game was a huge deal. And while he had to take a short break in 2020 after suffering a stroke and having heart surgery, he's still on the show today.
Rena Sofer
Over the course of his career, Leroy Jethro Gibbs had quite a few love interests. And if you cast your mind back to 2010, you might remember that he had a thing for attorney Margaret Allison Hart. Of course, their romance didn't last very long, and she appeared in only six episodes of NCIS overall, but she still made a fairly big impression. So has Rena Sofer outside of the show.
NCIS is one of her smaller roles, as this actress has appeared in countless other television shows, including General Hospital, The Bold and the Beautiful, The Chronicle, Coupling, and more.
Juliette Angelo
Juliette Angelo's NCIS storyline was a tough one. As the much-loved daughter of Tobias Fornell, Emily Fornell often made her way into the office to hang out with her dad and his colleagues. But while she seemed like a sweet girl, Emily was battling a lot of demons - including her struggle with narcotics. And while she remained sober for a while, she ultimately relapsed and died as a result.
Of course, this meant that Juliette's time on the show came to an end, but she's been able to keep working ever since. In recent years she's starred in Shameless, Trial of the Chicago 7, and Malibu Country.
Sasha Alexander
Sasha Alexander was one of the original NCIS characters. She took on a leading role during the first and second seasons and played Special Agent Caitlin Todd, an important member of the Major Case Response Team and a good friend and colleague of Gibbs. However, it's fair to say that her emotional ties to those she met did get her in a bit of trouble - so much so that she was murdered in season two.
Thankfully, actress Sasha Alexander is still alive and well today. She's been booked and busy for yeas, starring in multiple TV shows and movies. She's even made her mark as a director.
Weronika Rosati
If you don't remember Weronika Rosati appearing on your screens, that's to be expected. Although she made a mark with her beauty, her time on the show was very short-lived. In fact, she only appeared in one episode in 2013 when she took on the role of Ziva David's mother. But it seems as though she couldn't stay away, as she later appeared in two episodes of NCIS: Los Angeles as Vanya.
Although they were only small, these roles in American television shows were a big deal for Polish actress Weronika. Until that point, she had only really worked in her home country. She's still doing the same now.
Duane Henry
Everybody loves a British character, and Duane Henry brought that to NCIS in the form of British MI6 Intelligence Operative and NCIS International Desk Agent Clayton Reeves. Although he was only a guest of the show for season 13, his appearance was so well-received that he was given a leading role from seasons 14 through 15. Sadly, he was killed before he could continue his reign within the NCIS office.
As Duane Henry has been able to crack the American market, the British actor has been able to maintain his place in the limelight. In fact, his two most recent projects were Hallmark movies.
Millie Bobby Brown
You might be surprised to see this leading lady on this list, as Millie Bobby Brown is now one of the most famous actresses in the world, thanks to her role in Stranger Things. But before she got her big break on Netflix, Millie appeared in a 2014 episode of NCIS. To be more specific, she appeared as Rachel Barnes in the season 11 episode "Parental Guidance Suggested." In this, she was the daughter of Dr. Valerie Barnes and Commander Ryan Barnes.
Although Millie went on to star in Stranger Things, it seems as though she's now focusing her time on movies instead. At the time of writing, she has The Electric State movie in post-production.
Diane Neal
Diane Neal had a recurring role on NCIS from season seven through to season 12, and it was during this time that she became the coffee-drinking, hard-working Special Agent Abigail Borin. Although she was a member of the Coast Guard Investigative Service and worked in a different unit to Gibbs, it seemed as though they were almost the same person. That's why Tony hoped that they would one day get together.
Although Diane loved her time on the screen, she fractured her spine in 2013 and had to put her acting career on hold. In fact, she recently moved to Israel permanently.
Margo Harshman
If you cast your mind back to season 11, you might remember when it was revealed that McGee was flirting with an agent at the Department of Defense. Well, we later found out that was Delilah Fielding. As she became a more prominent member of the cast, we watched as she navigated her work life and her relationship - and she later became Mrs. Fielding-McGee. All in all, she appeared in 18 episodes.
For actress Margo Harshman, NCIS was a big deal and her longest stint on a TV show since she starred as Tawny Dean in Even Stevens. In 2023, though, she landed her first big movie role.
Meredith Eaton
Seeing Meredith Eaton step into the shoes of toxicologist and laboratory technician Carol Wilson in both NCIS and NCIS: New Orleans was a big deal for fans. Viewers loved the fact that she had such a strong bond with Abby and knew that the two women needed each other to survive amongst the large group of men in the industry. But this wasn't Meredith Eaton's first stint on a big TV show.
Previously, she starred in Family Law, Boston Legal, and MacGyver. In fact, she's a regular on prime-time television, and she even holds the record as the first female with dwarfism to have a leading role on prime-time TV.
Pancho Demmings
It's always the happy-go-lucky characters that get the most tragic storylines, and this was certainly the case for Gerald Jackson. He served as the assistant of NCIS Medical Examiner Dr. Donald Mallard, and he got on with everyone like a house on fire. And while he was a regular during season one of the show, he only appeared in 15 episodes as he was ultimately shot. Thankfully, he didn't die, but he didn't come back to the show.
Since his time on NCIS, actor Pancho Demmings has been here, there and everywhere. Although he hasn't quite landed his big break or been offered more than a one-episode stint, he's still working hard.
Abigail Breslin
Although Abigail Breslin was only eight years old when she appeared on NCIS, what you might not realize is that she was already pretty famous. In fact, she landed her first acting role two years before she became Sandy Watson in the episode "See No Evil," so working alongside big actors was nothing new to her. She was in a tough episode, though. Not only was she blind, but she was also kidnapped in this episode.
However, Abigail seems to have gotten used to appearing in scary dramas, as she's recently taken on lead roles in Scream Queens, Zombieland: Double Tap, and Slayers. She even served as the producer on Slayers.
Claudia Black
In the grand scheme of things, Claudia Black wasn't a very memorable character on NCIS. Although she blew viewers away with her beauty, this character had a lot to answer for. She was a bar owner, drug dealer, and snake enthusiast - and she only ever appeared in one episode in season seven. And during this episode, she was actually arrested for her crimes. So, that was the last we saw of her.
That wasn't the last time we saw Claudia Black, though. Since her one-episode stint, she's starred in many TV shows. But she now primarily works in video games, bringing animated characters to life.
Stephanie Mello
To this day, NCIS is one of Stephanie Mello's biggest roles. Filling the shoes of MTAC Tech Cynthia Sumner in season three was hugely exciting for the young actress, and all in all, she appeared in 14 episodes from 2005 to 2007. However, it's safe to say that her role wasn't a big one, and she primarily served as a helping hand around the office. You could say that she didn't really have her chance to shine.
The same can be said about her acting career since. After NCIS, she starred in one episode of Big Time Rush, but her IMDb resume stops there. It seems as though she hasn't acted since.
Rocky Carroll
In season five of NCIS, we were introduced to NCIS Director Leon Vance. And while he was only a recurring character to begin with, he's since made his mark as a main character - and he's actually still going strong today. As if that wasn't enough, the character also transitioned over to NCIS: Los Angeles for a few episodes from 2009 until 2014. So, you could say that he's an NCIS legend.
Of course, this show has kept Rocky Carroll pretty busy. But he's not just acted on the show, as he's also served as the director for over 20 episodes of the hit TV show so far.
Catherine Bell
Fans of both JAG and NCIS will know that Catherine Bell has more of an affiliate with the first TV show. After all, she served as Lieutenant Colonel Sarah MacKenzie for eight seasons from 1996 until 2005. This character rose through the ranks to become a fan favorite, so it was a shame when she left. But it all worked out in the end, as Catherine reprised her role in 2019 for three episodes of NCIS: Los Angeles.
In real life, Catherine's stint on this epic show thrust her into the limelight. But in recent years she's also won over fans with her role in The Good Witch. She even served as the co-executive producer of this show.
Susanna Thompson
We already know that Gibbs had a long history with women, and Army Lieutenant Colonel Hollis Mann was one of the few women who managed to tie him down for a short while. Although they had a serious relationship and were happy for the most part, their relationship ultimately ended after eight episodes. And while she could have had a bigger role within the NCIS team, Hollis decided against it and chose to retire instead.
Susanna Thompson hasn't retired, though. She's kept herself booked and busy since her days on the NCIS set, working on TV shows like Arrow, Timeless, Kings and many other shows.
Maria Bello
NCIS Special Agent and Psychologist Dr Jacqueline Sloane wowed fans with her impressive profiling skills from seasons 15 to 18, and most people would be lying if they said that they didn't want her to begin a relationship with Gibbs. After all, it seemed as though she held a fondness for him. But nothing romantic ever occurred between them, and Sloane eventually decided to leave the force to spend more time with her daughter.
Although NCIS proved to be a successful move for Maria Bello, she didn't exactly need it. She was already famous, and she's even more famous now. In fact, she recently served as the producer and story writer of The Woman King.
Jacqueline Obradors
When you look at Jacqueline Obradors' acting resume, her time on NCIS was a little fish in a big pond. And while she played Paloma Reynosa in three episodes in 2010, she didn't have a huge storyline and was gone before we could really get to know her. Thankfully, the actress has stayed booked and busy ever since - and recently she's joined the cast of Grey's Anatomy as a series regular.
As if that wasn't enough, she's also appeared in the hit TV show Daisy Jones & The Six and Bosch. And we think we'll be seeing more of her, too.
Darby Stanchfield
All in all, Leroy Jethro Gibbs was married four times - and one of those lucky ladies was Shannon Gibbs. And while Gibbs divorced from his three other wives, this wasn't the case for Shannon. While Gibbs was working abroad, Shannon and their daughter Kelly were murdered. As a result, we only saw Darby Stanchfield in seven episodes of NCIS between 2006 and 2015. She was talked about a lot after this, though.
After NCIS, Darby had a long stint of only bagging a few episodes of shows, but that all changed in 2020 when she was cast in a leading role as Nina Locke in Locke & Key.
Michelle Pierce
In 2010, fans of NCIS were first introduced to the character of Breena. With her beauty and her brains, Breena was able to charm Jimmy Palmer and they quickly entered into a relationship. In fact, they even got hitched as the seasons went on. And while she only appeared ever so often, it was still a shock to fans in 2021 when it was revealed that she had died of COVID-19.
But while she has oodles of talent, NCIS has been one of Michelle Pierce's only major roles. Although she's also starred in CSI: NY, Days of Our Lives, and Rules of Engagement, these were only small parts.