NCIShas been around for more than 20 years, and during that time many of its cast members have come and gone. The show has become legendary over the years, expanding into a successful franchise that features several satellite offices and a prequel series. TheNCISspinoffshave even brought all along their own iconic characters that have blended in well with the success of the franchise.

As with any show that has been on the air for more than two decades,a key to making the show so likable is the character development that comes with it. While theNCISteam may only have one original team member left, every old and newNCIScharacterhas undergone extensive stress and tension. Some have experienced more change than others, so it’s fun to look back on the actors and characters then and compare them to now.

11Sean Murray - Timothy “Tim” McGee

Seasons 1-22

Tim McGee is probably one of theNCIScharacters that have changed the most. In his first appearance on the show as a recurring character in season 1,McGee was shy and unsure of his capabilities. He was able to hold his own, but he was also intimidated by his superiors, Tony and Gibbs, because of his lack of experience.

By contrast,McGee is a confident, skillful agent inNCISseason 22. He has also risen in the ranks quite extensively, since he started off as a “probie” in the earlyNCISseasons and is now the second-in-command of the MCRT just after Parker. His skills as a special agent are especially noteworthy in how he uncovered Gabriel LaRoche’s undercover operation inNCISseason 22.

10Brian Dietzen - Jimmy Palmer

Jimmy Palmer also shares similar experiences of growth to his co-worker McGee.When Palmer first started out, he was only a Medical Examiner Assistantto the show’s ME, Ducky. While Palmer was highly intelligent and skilled, he also doubted his abilities as he kept comparing himself to his mentor.

Roscoe “Rocky” Carroll

Leon Vance

However, this changed over time.Palmer grew more confident and, ever since Ducky’s blessing and retirement, he has remained a competent Medical Examinerand team member. Palmer’s personal life has also grown as his confidence has. Between the first and most recentNCISseasons, Palmer has pursued several romantic relationships, something that he would not have felt comfortable doing in season 1.

9David McCallum - Donald “Ducky” Mallard

Seasons 1-20

In contrast to some of his colleagues,David McCallum’s Ducky Mallardhad a slower rate of change throughout of his time on the show. In his first appearance in season 1,Ducky was a very kind and confident character, with eclectic facts and stories. He was also always the lead in medical examinations.

This change was more so a professional decision than a personal one, reflecting Ducky’s desire to maintain high medical standards and support his friends all in one.

While Ducky’s personality did not necessarily change,he developed a tendency to let others take the lead as he got older. As he neared his retirement, Ducky used Palmer’s help more because he knew that Palmer would be the one to replace him eventually. This change was more so a professional decision than a personal one, reflecting Ducky’s desire to maintain high medical standards and support his friends all in one.

8Mark Harmon - Leroy Jethro Gibbs

Seasons 1-19

It is without a doubt thatMark Harmon’s Gibbschanged the most throughout his time on the show. In the early seasons ofNCIS,he was cold and reserved. While he respected his team and considered them to be like family, he struggled with letting people in, a result of the losses he had experienced over the years.

InNCIS: Origins, modern day Gibbs even begins journaling about the days following the loss of his family, implying more emotional growth has happened since his last appearance onNCIS.

By the laterNCISseasons, however, Gibbs was a changed man. While he still struggled with being vulnerable,Gibbs had learned to open up and share his struggles with others. He even started attending therapy and expressing his feelings, something a young Gibbs could rarely do.

7Rocky Carroll - Leon Vance

Seasons 5-22

Appearing for the first time as the temporaryNCISdirector in season 5 before becoming the official one in season 6,Rocky Carroll’s Leon Vanceexperienced some significant changes throughout of his time onNCIS. For one thing,when we first joinedNCIS, he was a boss but nothing else. It took time for him to get to know his team and learn how they work together.

By now,he has become possibly the best director that the MCRT could have. He is competent, intelligent, and knows when he has to protect the team. The biggest instance of this happened inNCISseason 22 when both McGee and Vance suspected LaRoche. To help McGee, Vance left LaRoche’s file open for McGee to see, which gave Vance plausible deniability and McGee the support he needed.

6Pauley Perrette - Abigail “Abby” Sciuto

Seasons 1-15

Abby Sciuto also had noticeable changes over the course of her time on the show. While she was always a sort of eclectic character with niche hobbies and interests when compared to the other members of her team, she softened a bit as a character as the seasons went on. In season 1, she was more of a flat character, butshe became much more rounded in later seasons.

The types of jokes she made also changed. In the earlier seasons, she had made a few sexual jokes, but this changed the longer that Abby was on the team. Perrette revealed in an interview withHELLO!thatshe did not like Abby’s sexual sideand, as a result, she became more involved in the character development to move Abby’s character growth in a different direction.

5Michael Weatherly - Anthony “Tony” DiNozzo Jr

Seasons 1-13

Tony DiNozzo had some of the best character growthof all theNCIScharacters. Throughout most of his time on the show, Tony was immature and showed a lack of respect towards his female colleagues. His conduct resulted in a lot of jokes, but underneath it all, it showed his lack of maturity. This changed in the years leading up to his departure.

Following the news of Ziva’s departure,Tony quietly began changing into a more mature and responsible man. He had always been an excellent agent, but his personal life did not mirror that same level of responsibility. However, it was Ziva’s death and the news that he had a daughter that caused Tony to quickly grow up and take responsibility for his and his daughter’s future.

4Cote de Pablo - Ziva David

Seasons 3-11

Cote de Pablo’s Ziva Davidstarted off as a private woman when she first joinedNCIS. However, as the team got to know her and learned to see past her relation to Ari,Ziva started to slowly open upto the rest of her team. She became not only a great agent but a great friend too.

Her openness and vulnerability are also highlighted in her relationship with Tony. In the beginning, it seemed shallow, but it became something deeper with time.While Ziva began as an outsider, she slowly earned the team’s trust, making her departure extremely shocking.

3Wilmer Valderrama - Nicholas “Nick” Torres

Seasons 14-22

Similar to many of his colleagues, Nick Torres also struggled to open up to others when he first joinedNCISin season 14.He began as an arrogant characterwho offered little to no explanation for his behavior. Over time, however, his story unfolded and so did his character.

Overall, Torres has followed the path of his colleagues, learning to be vulnerable after experiencing a difficult past.

With the reveal of Torres' traumatic childhood, his character has started to fit in morewith the rest of his team, since his personality now has a deeper explanation. He has also grown particularly close with his colleagues and has learned to be vulnerable again after his failed relationship with Ellie Bishop. Overall, Torres has followed the path of his colleagues, learning to be vulnerable after experiencing a difficult past.

2Diona Reasonover - Kasie Hines

Seasons 15-22

As one of the newer characters onNCIS,Kasie has not had as much room for character growth as some of the others. She also has not experienced nearly the same level of stressful storylines that have impacted her colleagues. However, she has experienced some changes, and it has to do with her work.

As a forensic scientist, Kasie does not leave the lab often, but recentNCISseasons have shown her interacting outside more often. This shows her professional growth as she learns the rules of doing fieldwork alongside her work in the lab. It also shows howthe team has learned to see her as more than just a lab technician, since she can offer help in many different ways.