Mark Harmon's Age Revealed: 7 Key Milestones As The NCIS Legend Turns 74 And Returns To Gibbs' Role In 2025

The question of "how old is Mark Harmon" is one of the most frequently searched queries in television history, a testament to the enduring appeal of the actor best known for playing Special Agent Leroy Jethro Gibbs on the global phenomenon, NCIS. As of the current date, December 10, 2025, the American icon is 74 years old, an age that has brought with it some of the most exciting and personal news of his career, including a highly-anticipated return to the NCIS universe and a major new role in his personal life.

Harmon, whose career spans over five decades, continues to defy expectations, maintaining a rugged, youthful presence that makes his actual age a continuous source of curiosity for fans worldwide. His 74th year has proven to be anything but a quiet retirement, marked by a crossover event with the spin-off NCIS: Origins and a deeply personal family milestone that has thrilled his supporters.

Thomas Mark Harmon: A Comprehensive Biographical Profile

Thomas Mark Harmon was born into a famous family, a background that set the stage for his own multifaceted career. His journey from a college football star to one of television’s most recognizable faces is a story of versatility and enduring appeal.

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• Full Name: Thomas Mark Harmon
• Date of Birth: September 2, 1951
• Current Age (as of Dec 10, 2025): 74 years old
• Place of Birth: Burbank, California, U.S.
• Parents: Tom Harmon (Heisman Trophy winner, sportscaster) and Elyse Knox (actress, fashion designer)
• Spouse: Pam Dawber (Married since 1987)
• Children: Sean Thomas Harmon and Ty Christian Harmon
• Education: University of California, Los Angeles (UCLA) (Cum Laude, B.A. in Communications)
• Notable Career Roles: Dr. Robert Caldwell (*St. Elsewhere*), Simon Donovan (*The West Wing*), and most famously, Special Agent Leroy Jethro Gibbs (*NCIS*)

The 2025 Gibbs Comeback: New Role and Crossover Event

Despite stepping away from his full-time role on NCIS in 2021, Mark Harmon's presence as Leroy Jethro Gibbs remains the heart of the franchise. The biggest news of 2025 for fans was the confirmation of his return, not just as the beloved character, but also in a new capacity.

A Special Appearance in NCIS and NCIS: Origins

The veteran actor is slated to make a special guest appearance in a major crossover event between the flagship series, NCIS, and the highly anticipated prequel, NCIS: Origins. This event, scheduled for Tuesday, November 11, 2025, is set to be a massive moment for the franchise.

Harmon's initial departure saw Gibbs relocate to Alaska, finding peace after a long and storied career. His return to the screen, even for a cameo, connects the new generation of the show—which features a younger version of Gibbs—with the legendary character who defined the series for nearly two decades.

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In addition to his on-screen appearance, Harmon serves as an executive producer for NCIS: Origins, which stars Austin Stowell as the young Gibbs. This off-screen role ensures that the legacy and character integrity of Leroy Jethro Gibbs are maintained, providing a vital link between the past and present of the NCIS universe.

From UCLA Quarterback to Hollywood Legend: Harmon's Unexpected Path

Long before the badge and boat-building, Mark Harmon was known for his athletic prowess. His early life was dominated by sports, a path that could have led to a completely different career.

College Football Star

Harmon was a standout college athlete, playing quarterback for the UCLA Bruins from 1972 to 1973. He was recognized for his "all-round excellence" with the National Football Foundation Award in 1973. His talent was undeniable, leading him to receive professional football offers upon graduation.

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However, in a pivotal decision that changed the course of television history, Harmon declined those professional offers to pursue acting. He initially worked in advertising, as a shoe company representative, and as a carpenter—a skill he would later famously incorporate into his NCIS character's hobby of building boats.

Career-Defining Roles Beyond Gibbs

While Gibbs is his most iconic character, Harmon's career is marked by versatility. In the 1980s, he garnered significant attention for his role as Dr. Robert Caldwell on the medical drama St. Elsewhere. In 1986, he was famously named the "Sexiest Man Alive" by People magazine, cementing his status as a major Hollywood heartthrob. Later, he earned an Emmy nomination for his guest role as Secret Service Agent Simon Donovan on The West Wing, proving his ability to shine in complex, dramatic roles.

Personal Life Milestones: Grandfatherhood and Enduring Marriage

At 74, Mark Harmon is celebrating not only a career resurgence but also major family milestones, highlighting the private life he and his wife, Pam Dawber, have fiercely protected for decades.

A 38-Year Hollywood Marriage

Mark Harmon and actress Pam Dawber, known for her role in Mork & Mindy, have one of Hollywood’s most enduring and private marriages, having tied the knot in 1987. They share two sons, Sean Thomas Harmon and Ty Christian Harmon. Sean is particularly notable to NCIS fans, as he has appeared in several episodes playing a younger version of his father's character, Gibbs.

The Joy of Becoming a Grandfather in 2025

One of the sweetest pieces of news for the Harmon family in 2025 was the arrival of a new generation. Mark Harmon and Pam Dawber became first-time grandparents, a rare family update that delighted fans. This new role adds a beautiful, quiet chapter to the life of the actor who has spent so much of his career in the public eye, yet cherishes his private, family-focused life away from the spotlight.

The fact that Mark Harmon is 74 and still actively involved in major television projects, both in front of and behind the camera, is a testament to his passion for the craft. His longevity, combined with his recent family joy and his highly anticipated return as Gibbs in the NCIS crossover, ensures that the legendary actor remains a current and compelling figure in the entertainment world.