‘NCIS’ Star Mark Harmon Reveals Chance Phone Call That Became His Big Break Into Acting

Michelle Stein April 19, 2026, 10:17 am

Mark Harmon, NCIS — Alberto E. Rodriguez/Getty Images

What To Know

Mark Harmon revealed that a spontaneous phone call to producer Jack Webb led to his first acting opportunity.
It allowed him to land an early role in Adam-12.
Harmon’s career progressed from supporting film and TV roles to starring as special agent Leroy Jethro Gibbs on NCIS.

NCIS star Mark Harmon recently opened up about a chance call that led to his big break into acting.

In a clip from Mark’s appearance on The Fifth Column podcast posted to YouTube on April 16, Harmon opened up about switching careers from a merchandising director to an actor.

Mark — the son of Hollywood actress Elyse Knox and Heisman-trophy-winning football legend and sports broadcaster Tom Harmon — kicked off his acting career with a 1973 guest appearance on Ozzie’s Girls. He did so thanks to his sister, Kristin, the wife of actor and singer Ricky Nelson, who starred in The Adventures of Ozzie & Harriet and Ozzie’s Girls.

“When the advertising stuff kind of stopped being… I just knew I had to get out of that and do something else,” Mark explained on the podcast.” I said that to my parents. I had been in acting class, and I had been going and doing that, and I didn’t know where to go from there. I didn’t have an agent. I didn’t know what to do.”

One day, Mark said that he was watching Dragnet and saw the studio indent for the show’s production company, Mark VII Limited. He then cold-called actor and producer Jack Webb, who owned and operated Mark VII Limited. “I looked it up in the phonebook, and I called,” he explained, noting that the secretary who answered “didn’t have to put me through, but she did.”

“We talked for a couple minutes, and he said, ‘Why don’t you come in and talk to me?'” Mark recalled, of his chat with Webb. “And I said ‘OK,’ and I went into Universal, and I went into Mark VII, which at that time at Universal, was a big enchilada, man.”

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Ultimately, Mark appeared as Officer Gus Corbin in a 1975 episode of Adam-12, produced by Mark VII.

Of the chance phone call with Webb, he pointed out, “He had to be nice, right? If he just goes, ‘I’m not taking that call, it’s over.'”

In addition to Adam-12, Mark made guest appearances in Police Woman in 1975 and Laverne & Shirley in 1976. He went on to snag supporting roles in films like Comes a Horseman (1978) and Beyond the Poseidon Adventure (1979). In 1983, Mark landed the role of Dr. Robert Caldwell in the series, St. Elsewhere. He was also named People Magazine’s Sexiest Man Alive in 1986.

After starring in Summer School (1987), The Presidio (1988), Crossfire Trail (2001), and Freaky Friday (2003), he was cast as special agent Leroy Jethro Gibbs in NCIS. Mark left the iconic role in 2021 after 19 seasons, and later reprised Gibbs in NCIS: Origins.

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