While Mark Harmon stands out as the primary representation of Leroy Jethro Gibbs inNCIS, several other actors have portrayed the character in the franchise. The multiple representations of thecentralNCIScharacterhave created a rich offering of who Jethro Gibbs is and how he operates.The character was first established inJAGand the flagship series in 2003, when theNCISfranchise was getting off the ground. Once the series set course, other character portrayals were included to provide insight into how Gibbs developed into the Special Agent-in-Charge.
In the flagship series,various actors portrayed Gibbsat different times in his life to paint the complete picture of the supervisor. While the moments were brief, tucked within the procedural’s regular formula, the series' choice to show Gibbs at different phases of his life helped better understand the character’s role in thesharedNCISuniverse. While it seems nearly impossible that anyone other than Mark Harmon could step into the role, different character representations from differing actors enhanced the central Gibbs character on the flagshipNCISseries. Alternate representations made gave the stubborn and reserved leader more complexity.
The character’s development will expand sincea new actor will step into the Jethro Gibbs rolefor the first time in a decade. Austin Stowell will take over the character in theNCIS: Originsspinoff. The prequel series will rewind the clock to 1991, an emotional time for Gibbs. As such, the prequel version of the character will surely add layers of emotion and vulnerability to the character. While Mark Harmon established Gibbs, his version is far from conclusive, and the more emotional elements that Stowell will bring to the role are just as much Gibbs as his tough exterior.
4Mark Harmon
Adult Gibbs, NCIS
Mark Harmon established the Leroy Jethro Gibbs character in the flagshipNCISseries.The character was first introduced inJAG,a 1990s legal procedural series, whenNCISlaunched as a backdoor pilot in 2003 inJAGseason 8, episode 20, “Ice Queen,” and 21, “Meltdown.” On the flagshipNCISseries, the actor portrayed the character for nearly two decades untilMark Harmon exitedNCISin season 19. Harmon established a substantial presence as the Gibbs character and is one of the most belovedNCIScharacters ever. In the flagship series, the adult Gibbs character has trademark characteristics.
While we know that Gibbs experienced trauma in the early 1990s, by the timeNCISlaunched a dozen years later in 2003, Gibbs had learned to control his emotions.Harmon’s Gibbs was indelibly smooth and imperviousto those around him. Although he had lost his wife and daughter, Gibbs was rarely affected. Instead, the agent opted for a short temper that included a lot of slaps to the back of the heads of his team. That said, ultimately, Harmon’s character had a soft side, shown inGibbs' relationship with Ziva, Abby, and occasionally Gibbs or Tony.
Mark Harmon will return toNCISto narrate and executive produceNCIS: Origins.
As the Special Agent-in-Charge of the Major Case Response Team at Washington’s NCIS Headquarters,Harmon’s Gibbs had a massive role in the agency, and, therefore, his character carried over to manyNCISspinoff shows, like hisNCIS: New Orleansappearance. Although he stepped away from the role in 2021, Harmon maintains one of the most robust presences in theNCISfranchise. Harmon’s version of Gibbs is remembered as a fierce team leader who would do anything to protect those he worked with and the families he served. His sharp instincts, quick wits, and short temper were essential to the character.
3Sean Harmon
Young Gibbs, NCIS
Sean Harmon established the young Gibbs characterin the flagshipNCISseries. Harmon first appeared as young Gibbs inNCISseason 6, episode 4, “Heartland,” and the introduction of the young Gibbs character made it one of thebest episodes ofNCIS.The episode explored the character’s past when a case brought Gibbs' team to his hometown of Stillwater, Pennsylvania. When he was home, Gibbs reunited with his father, and the reunion, as well as the town itself, evoked memories of Gibbs' coming-of-age. The memories were portrayed as flashbacks, and Mark Harmon’s son portrayed young Gibbs in the snippets.
As the flagship series unfolded, Sean Harmon would return as young Gibbs to continue to unfold elements of Gibbs' past. During his handful of appearances onNCIS,Sean Harmon established a shy, reserved version of Leroy Jethro Gibbs. The actor’s portrayal of the character sometimes predated Gibbs' time in the Marine Corps, with Gibbs as an adolescent. As such, while he was headstrong, like the adult version of his character, Sean Harmon’s Gibbs was still finding his place in the world and had yet to experience the trauma of war and the sudden loss of his immediate family members.
Watch Sean Harmon appear in anNCISspinoff show as Charlie Connor inNCIS: Los Angelesseason 6, episode 20, “Rage.”
WhileNCIS: Originswill revive the young Gibbs character, Sean Harmon, who has made a career as a stuntperson and coordinator, did not reprise his role. Instead,NCIS: Originsis taking a risk. Still, Harmon will return with his father to executive produce the series. The younger Harmon was the one who had the idea for the Gibbs prequel series, and he has been instrumental in its development. That said, if Harmon had resumed his character portrayal, he would have been the perfect age. In 2024, Sean Harmon will be 36, and Leroy Jethro Gibbs will be 37 in 1991.
2Micah Tayloe Owens
Child Gibbs
While Gibbs is mainly shown as an adult in the series,NCISseason 11, episode 24, “Honor Thy Father,” made a noteworthy exception, portraying Gibbs as a child. In the episode, Gibbs traveled to his hometown after he learned that his father, Jackson Gibbs, had died. The legendaryThe Waltonsactor Ralph Waiteportrayed the elder Gibbs. The character was introduced along with the young Gibbs character inNCISseason 6, episode 4, “Heartland.” Jackson Gibbs was an essential character, and as such, the series had to say goodbye when Ralphe Waite died at 85.
In “Honor Thy Father,“Gibbs was shown as a child in flashbacksto the special agent’s past. In the flashbacks, Micah Tayloe Owens' Gibbs built a toy boat with his father. At the same time, Jackson Gibbs explained details about his relationship that were difficult for the child to conceptualize. The memories added depth to the episode’s tribute, painting a fuller picture of what Jethro and Jackson’s relationship looked like. The flashbacks helped to build the gravity of the moment. In the episode’s conclusion, Jethro and Jackson gave the boat to Gibbs' mother, and adult Gibbs attended his father’s funeral.
The child version of Gibbs was the most removed from the horrors he faced.
The young actor was an excellent cast for the part sinceMicah Tayloe Owens was a spitting image of Sean Harmon’s young Gibbscharacter. The kid version of the Gibbs character further enhanced the robust rapport that Gibbs had with theNCISaudience, showing the Special Agent-in-Charge at another phase of his life. The flashbacks also established thatGibbs built boats in his basement inNCISbecause it was a hobby he established with his dad. Owens' representation of Gibbs was unique since the child version of Gibbs was the most removed from the horrors he faced later in life.
1Austin Stowell
NCIS: Origins
The Gibbs character will experience a total refresh inNCIS: Origins.The Hating Game’sAustin Stowell was cast as young Gibbs, and as such, the Gibbs character will have its first fresh face in a decade since Micah Tayloe Owens stepped into the role in 2014. Stowell will portray the Gibbs character at a different time in his life than audiences are used to seeing, with theNCIS: Originsspinoff rewinding the clock to 1991 when Gibbs was starting as an NCIS agent. 1991 is the same year that Gibbs lost his wife and daughter, Shannon and Kelly.
While the flagshipNCISseries touches onwhat happened to Gibbs' family inNCIS,the prequel series will explore Gibbs' trauma, including how it affected Gibbs' career change. Gibbs was in the Marine Corps before joining the titular agency, with the tragedy involving his wife and daughter leading him to NCIS.A drug dealer murdered Shannon and Kellyafter Shannon agreed to testify against him, and Gibbs found out about their death upon waking from a coma he suffered following an explosion in the war in Kuwait. After he learns of their deaths and NCIS investigates, he joins the agency.
Stowell’s grieving Gibbs will be a subversion of Harmon’s level-headed leader.
Since Gibbs will be at a different stage in his life, Stowell has promised that his representation of the character is different from the Gibbs that audiences are used to seeing. In a comment forEntertainment Weeklyahead of the fall 2024-2025 TV cycle,Stowell said his character will vary from what audiences expect to seebecause he will portray the Gibbs character during a time in his life when he is experiencing pain. Stowell said his character is"not the guy that the fans are used to"since Stowell’s grieving Gibbs will be a subversion of Harmon’s level-headed leader.
Stowell’s variation of the Gibbs persona will create a new version of the character, and that could be what’s needed to take theNCISfranchise into a new era. While Stowell’s Gibbs will go back in time, everything about theNCIS: Originsseries will help to refresh the franchise. Mark Harmon’s Gibbs is irreplaceable, and other actors have already established a rapport with the character’s youth. That said, Stowell’s young Gibbs could be the missing piece that ties it all together, completing Leroy Jethro Gibbs’NCISstory.
NCIS: Originspremieres on CBS on July 10, 2025, at 9 pm Eastern.
NCIS
Cast
NCIS is a television series that follows a team of special agents from the Naval Criminal Investigative Service. Premiering in 2003, the show explores various cases involving Navy and Marine Corps personnel, ranging from murder and espionage to terrorism and stolen submarines.
NCIS: Origins is set in 1991, preceding the events of the original series. The series introduces Leroy Jethro Gibbs as a new special agent at NCIS Camp Pendleton. Under the leadership of NCIS legend Mike Franks, Gibbs navigates his role within a tenacious, unconventional team.
