Mark Harmon is back as Leroy Jethro Gibbs in NCIS: Origins Season 3. However, this is not a return to the original NCIS series as a regular cast member. Harmon appears throughout Season 3 as older, present-day Gibbs in a storyline connected to his past during the 1990s.

The return marks another major chapter in Harmon’s long relationship with the NCIS franchise after he left the original series in 2021 following 18 seasons as Gibbs.

Introduction

Mark Harmon remains one of the most recognizable television actors in the world, largely because of his iconic portrayal of Leroy Jethro Gibbs on CBS’s long-running crime drama NCIS.

In 2026, Harmon is once again appearing on screen as Gibbs through NCIS: Origins, the prequel series that explores the early career of the character.

The development is significant because Harmon left the regular cast of the original NCIS in 2021 after 18 seasons.

However, his 2026 return should not be confused with a permanent return to the original NCIS team.

Instead, Harmon is appearing as the older, present-day version of Gibbs in NCIS: Origins Season 3. The storyline connects Gibbs’ current life with events from his early career at Camp Pendleton in the 1990s.

The return gives longtime NCIS viewers another opportunity to see Harmon in one of his most famous roles while allowing the franchise to explore another chapter of Gibbs’ life.

What Happened With Mark Harmon in 2026?

The biggest Mark Harmon development in 2026 is his return as Gibbs in NCIS: Origins.

CBS confirmed that Harmon would appear in all episodes of Season 3 as part of a present-day mystery connected to Gibbs’ past.

Season 3 premiered in October 2026 and follows two connected timelines.

One storyline focuses on older Gibbs in the present day, while another continues the story of young Gibbs during the 1990s.

Austin Stowell continues to portray the younger version of Gibbs, while Harmon plays the older version.

This gives viewers two different versions of the same character within one series.

Harmon is also involved with NCIS: Origins behind the scenes as an executive producer and continues to narrate the series.

Is Mark Harmon Returning to the Original NCIS?

This is an important distinction.

Mark Harmon has returned to the NCIS universe, but there is no confirmed announcement that he has permanently returned to the original NCIS series as a regular cast member.

His confirmed 2026 appearance is in NCIS: Origins.

The original NCIS follows the investigative team based in Washington, while NCIS: Origins explores Gibbs’ early career and now includes a present-day storyline involving the older Gibbs.

Key facts about his 2026 return

• Mark Harmon returns as older Leroy Jethro Gibbs.
• He appears throughout NCIS: Origins Season 3.
• Austin Stowell continues playing young Gibbs.
• Harmon remains an executive producer.
• Harmon continues as narrator of the prequel.
• Season 3 includes a present-day mystery connected to Gibbs’ 1990s history.
• There is no confirmed permanent return to the original NCIS series.

Why Did Mark Harmon Leave NCIS?

Mark Harmon left the regular cast of NCIS during Season 19 after portraying Gibbs for 18 seasons.

His departure was written into the story rather than ending with Gibbs’ death.

In the Season 19 episode “Great Wide Open,” Gibbs completes an investigation in Alaska and makes the decision to remain there instead of returning to Washington.

The ending gave Gibbs a peaceful new chapter away from his former NCIS responsibilities.

Harmon later explained that the decision was connected to timing, fatigue and keeping the character’s story fresh and meaningful.

He also made clear after leaving the show that he had not retired from acting.

That distinction has become particularly relevant following his return to NCIS: Origins.

Mark Harmon’s NCIS Career

Mark Harmon’s association with Gibbs is one of the defining chapters of his acting career.

The character first appeared in the JAG universe before becoming the central figure of NCIS.

When NCIS became its own series in 2003, Harmon took on the leading role of Gibbs.

For nearly two decades, Gibbs served as the leader of the show’s investigative team.

His character became known for his calm personality, strong leadership, loyalty and strict approach to solving cases.

Harmon remained at the center of the series through numerous cast changes and storylines.

Important milestones in Mark Harmon’s NCIS career

• Harmon played Gibbs for 18 seasons on NCIS.
• Gibbs became the central leader of the investigative team.
• Harmon became involved with the franchise behind the scenes.
• He left the regular cast during Season 19.
• Gibbs chose to remain in Alaska.
• Harmon later became narrator of NCIS: Origins.
• He also became an executive producer of the prequel.
• He made additional appearances as Gibbs after leaving the original series.
• In 2026, he returned for a full-season storyline in NCIS: Origins.

Harmon’s long association with the character helped turn Gibbs into one of television’s best-known fictional investigators.

What Is NCIS: Origins About?

NCIS: Origins is a prequel to the original NCIS.

The series goes back to the early 1990s and follows a younger Leroy Jethro Gibbs at the beginning of his career with the Naval Investigative Service.

Austin Stowell plays young Gibbs.

The series explores the people, experiences and cases that helped shape the character before the events of the original NCIS.

Mark Harmon narrates the series and is also an executive producer.

Season 3 expands his on-screen role by making older Gibbs an important part of the present-day storyline.

This creates a connection between the younger Gibbs story and the character that longtime viewers already know from NCIS.

Mark Harmon’s Gibbs Return Is Different From His Original NCIS Role

One of the most interesting aspects of Harmon’s 2026 return is that he is not simply returning to his previous job as the head of the NCIS team.

In the original series, Gibbs was an active federal investigator working with his team in Washington.

In NCIS: Origins Season 3, Harmon portrays an older Gibbs who has already lived through the events that shaped the character.

The present-day storyline begins with Gibbs living in Alaska.

His peaceful retirement is disrupted when events connected to his past come back into his life.

This approach allows the franchise to bring Gibbs back without simply undoing the ending of his original NCIS storyline.

Mark Harmon and His Life Outside NCIS

Although Mark Harmon has spent decades in the public eye, he has generally kept his personal life relatively private.

Harmon has been married to actress Pam Dawber since 1987.

Dawber is particularly known for her roles in Mork & Mindy and My Sister Sam.

The couple have two sons, Sean and Ty.

Unlike many celebrity couples, Harmon and Dawber have generally avoided making their private lives a major part of their public careers.

Their long marriage has attracted attention because of its longevity, but the couple have continued to maintain a relatively low profile.

This is one reason why significantly more public information exists about Harmon’s acting career than about his everyday personal life.

Mark Harmon and His Son Sean Harmon

Mark Harmon’s family also has a direct connection to the NCIS franchise.

His son Sean Harmon has worked within the franchise and is an executive producer on NCIS: Origins.

Sean also previously appeared in NCIS as a younger version of Gibbs.

That gives the Harmon family an unusual connection to the character.

Mark Harmon established the primary television version of Gibbs, while Sean previously portrayed a younger version of the character.

Sean’s work behind the scenes on NCIS: Origins has continued the family’s involvement with the franchise.

Is Mark Harmon Retired?

No confirmed information indicates that Mark Harmon has retired from acting.

After leaving NCIS, Harmon explained in interviews that his departure from the series should not be interpreted as retirement.

His continued involvement with NCIS: Origins further demonstrates that he remains active in entertainment.

The major change was his decision to step away from the demanding schedule of the original NCIS, rather than permanently ending his acting career.

His 2026 return shows that Harmon remains willing to revisit Gibbs when the story and timing are right.

What Does Mark Harmon Do on NCIS: Origins?

Harmon has several important roles on NCIS: Origins.

Actor

He plays the present-day version of Leroy Jethro Gibbs.

Narrator

Harmon narrates the series, helping connect the younger Gibbs storyline with the larger NCIS universe.

Executive Producer

He is also an executive producer, giving him a creative role behind the camera.

His involvement therefore goes beyond simply appearing in individual episodes.

What Happened to Gibbs After NCIS?

Within the fictional storyline, Gibbs leaves his previous life in Washington and remains in Alaska.

His decision is presented as a new chapter after decades of service.

Instead of returning to the NCIS team, he chooses a quieter life away from his former responsibilities.

The third season of NCIS: Origins changes that situation.

Events connected to Gibbs’ past begin to interfere with his peaceful retirement.

That creates a new reason for the older Gibbs to become involved with a mystery connected to his earlier career.

Why Mark Harmon’s Return Matters to NCIS Fans

Mark Harmon’s return matters because Gibbs was not simply another character on NCIS.

For 18 seasons, he was one of the primary faces of the franchise.

His departure represented a major change for the series.

However, the franchise continued to expand, eventually giving Gibbs his own prequel series.

NCIS: Origins offers a different way to tell Gibbs’ story.

The series can explore his early career through Austin Stowell while simultaneously allowing Harmon to portray the older Gibbs.

This structure gives longtime viewers additional information about the character without requiring Harmon to return permanently to his previous role on the original series.

What Happens Next for Mark Harmon?

The immediate confirmed development is Harmon’s continued involvement in NCIS: Origins Season 3.

The season consists of a present-day storyline involving older Gibbs and a parallel storyline involving young Gibbs during the 1990s.

The season began airing in October 2026.

Beyond Season 3, Harmon’s future plans have not been fully established.

There is currently no confirmed information that he will permanently return to the original NCIS series.

There is also no confirmed announcement that he is retiring from acting.

Therefore, claims about a full-time return to the original series should be treated as speculation unless officially confirmed.

Mark Harmon’s Career Beyond NCIS

Although Gibbs is now the role most closely associated with Mark Harmon, his career began long before NCIS.

He appeared in numerous television programs and films before taking on the role that would define his later career.

His earlier television work included roles in productions such as St. Elsewhere and Chicago Hope.

Harmon became one of television’s most recognizable actors during his years on NCIS.

The success of the series transformed Gibbs into an internationally recognized television character.

However, Harmon’s career extends well beyond the role.

His continued work after leaving NCIS demonstrates that his professional life has not been limited to one series.

The Bigger Picture: Mark Harmon’s Legacy as Gibbs

Gibbs became popular partly because of the character’s understated personality.

He was rarely the loudest person in the room.

Instead, Gibbs was portrayed as a disciplined leader who relied on experience, observation and loyalty.

Harmon brought a restrained style to the role that helped distinguish Gibbs from many traditional television investigators.

That performance helped sustain the character through years of changing cast members and storylines.

His 2026 return does not erase his previous departure from NCIS.

Instead, it provides another chapter for a character whose fictional story now spans several decades.

The NCIS: Origins format allows viewers to see both the younger Gibbs and the older Gibbs, giving the franchise a way to connect its past and present.

What We Know About Mark Harmon in 2026

The clearest confirmed picture of Mark Harmon’s professional life in 2026 is:

• He remains closely connected to the NCIS franchise.
• He appears as Gibbs in NCIS: Origins Season 3.
• He portrays the present-day version of Gibbs.
• Austin Stowell plays young Gibbs.
• Harmon remains the narrator of the series.
• He is an executive producer.
• His Season 3 storyline involves a present-day mystery connected to his 1990s Camp Pendleton history.
• There is no confirmed permanent return to the original NCIS series.
• Harmon has not announced a permanent retirement from acting.
• He continues to keep much of his personal life private.

For fans searching for the latest Mark Harmon news, the key point is simple: Gibbs is back on screen, but through NCIS: Origins rather than a confirmed permanent return to the original NCIS.

FAQs

Is Mark Harmon returning to NCIS in 2026?

Mark Harmon has returned to the NCIS universe through NCIS: Origins Season 3. He appears as older Leroy Jethro Gibbs throughout the season. There is no confirmed announcement that he has permanently returned to the original NCIS series.

Is Mark Harmon still playing Gibbs?

Yes. Mark Harmon continues to play Leroy Jethro Gibbs in NCIS: Origins. He portrays the older, present-day version of the character, while Austin Stowell plays young Gibbs.

Why did Mark Harmon leave NCIS?

Harmon left the regular cast during Season 19 after 18 seasons. Gibbs’ story ended with him deciding to remain in Alaska rather than return to his previous NCIS position in Washington.

Is Mark Harmon retired?

No permanent retirement has been announced. Harmon has previously said that leaving NCIS did not mean he had retired, and he continues to work on NCIS: Origins.

Who plays young Gibbs in NCIS: Origins?

Austin Stowell plays the younger Leroy Jethro Gibbs. The series follows Gibbs during the early 1990s before the events of the original NCIS.

Who is Mark Harmon’s wife?

Mark Harmon’s wife is actress Pam Dawber. They married in 1987 and have two sons, Sean and Ty.

Does Mark Harmon have children?

Yes. Mark Harmon and Pam Dawber have two sons, Sean Harmon and Ty Harmon. Sean has also worked within the NCIS franchise.

When did Mark Harmon leave NCIS?

Harmon left the regular cast of NCIS during Season 19 in 2021. Gibbs chose to remain in Alaska rather than return to his former position.

What is Mark Harmon doing in 2026?

In 2026, Harmon is appearing in NCIS: Origins Season 3 as older Gibbs. He is also involved with the series as narrator and executive producer.

Will Mark Harmon return to the original NCIS?

There is currently no confirmed announcement establishing a permanent return to the original NCIS. His confirmed 2026 return is through NCIS: Origins.