Mark Harmon comes from a family of celebrities, and recently he shared some advice from his father, sporting legend Tom Harmon.

Actor Mark Harmon is known to most as Leroy Jethro Gibbs from the hugely successful TV show NCIS. But did you know that the actor comes from a very famous family? Mark’s dad, for instance, was none other than former NFL star and broadcaster Tom Harmon. And in February 2019 the star spoke to People magazine about some profound – and slightly profane – advice that his father had imparted to him. Yet while the anecdote may sound like an NCIS scene between Gibbs and Jackson, it’s totally real – and something that Mark has carried with him throughout his whole life.

It’s fair to say that the Harmon family tree is full of famous faces. At the top, there’s football star Tom and his wife, Elyse Knox, who was an actress. Then, of course, there’s Mark himself – a successful TV star. Elsewhere, Mark’s sister Kristin wed The Adventures of Ozzie & Harriet actor Rick Nelson. And from that union came actress Tracy Nelson and rockers Matthew and Gunnar Nelson.

What’s more, Mark is also married to someone from the celebrity world. In 1987 he got hitched to Mork & Mindy actress Pam Dawber, with the couple going on to have two sons: screenwriter Ty and actor Sean. It goes without saying, then, that the Harmons are used to being in the public eye. But you won’t catch any of the family on Facebook or Instagram; they maintain their privacy intensely.

Remarkably, though, Mark was raised without even knowing how famous his father was. “It didn’t hit me until one day when I was riding in the car with my father in Ann Arbor, Michigan. I was maybe eight and could barely see above the dashboard, and we stopped at a crosswalk,” he told Closer Weekly in 2018.

“Suddenly, we were surrounded by people who recognized my dad and were really thrilled to see him,” Mark went on. “I remember looking at this man I thought I knew so well and thinking, ‘Who are you?’” Football legend Tom wasn’t one to make a big deal about his achievements, after all. For instance, Mark didn’t even know for a while that his dad was the owner of a Heisman Trophy.

In fact, Mark only found out about the award from “a kid at the park,” according to northwest Indiana newspaper The Times. Tom hadn’t even mentioned it to his son. “I didn’t know much about his celebrity, and that was a credit to him,” Mark explained. “He was just Dad – and a good one. He didn’t come home and say, ‘Hey, I’m gonna be on TV in ten minutes. Let’s all watch.’”

Image: Athletic Department Records, Bentley Historical Library, University of Michigan

However, there was even more to Tom’s remarkable past than the awards and the fame. Mark’s well-known father had also been in the Army Air Corps, you see, serving as a fighter pilot during World War II. And he had some truly amazing stories to tell as a result. For instance, Tom went MIA not once, but twice during the conflict.

Image: Alumni Association Records, Bentley Historical Library, University of Michigan

If that weren’t incredible enough, Tom also cheated death twice. In April 1943 his plane – dubbed Old 98 after his jersey number – crash-landed in a jungle in the Republic of Suriname, which was then known as Dutch Guiana. There had been six crew members on board, but Tom was the only survivor. And the pilot persevered alone for four days in the wilderness before being rescued.

Tom’s second act of bravery came that same year, when he bailed out of a gunned-down plane over China. Upon landing, the pilot saw that his parachute was covered in bullet holes, and he pretended to be dead so that the enemy fighters would leave. Later on, Tom’s bride, Elyse, would make her wedding dress from the remains of this very parachute.

Image: Alumni Association Records, Bentley Historical Library, University of Michigan

Then, once the war was over, Tom returned to football and joined the Los Angeles Rams. Unfortunately, though, the veteran’s experiences in the war had taken a toll on him. Unable to play as effectively as he had done before, he therefore retired from football and became a broadcaster. Tom would later say that broadcasting was the only profession he’d ever wanted.

And, interestingly, Mark actually came close to following in the footsteps of his father. When he played football at Pierce College as a youngster, scouts took an interest. The budding sportsman even ended up playing for UCLA. Ultimately, though, Mark wasn’t interested in a football career. Instead, he earned himself a degree in communications and aspired to become an actor.

Image: Chris Bergman/Fotos International/Getty Images

And though, as we know, said choice eventually paid off, it took a while for Mark to make it as a leading man. At the start of his career, he performed in TV shows that faded into obscurity before too long, including Sam, 240-Robert, Flamingo Road and Charlie Grace. But in the early ’80s, Mark finally got his big break. The actor was cast as Robert Caldwell on doctor drama St. Elsewhere, which ran from 1982 to 1988.

Yes, the show catapulted Mark into acting fame – and also won him a notable accolade. In 1986 Mark was named as People’s Sexiest Man Alive, becoming only the second person to ever hold the title. The magazine called him “the new definition of sexy,” in fact, and noted his “gleaming grin, chiseled pecs and piercing blue eyes.”

Yet when Mark spoke to People for the occasion, the interview went much deeper than just talk of his famous looks. Surprisingly, in fact, the actor revealed that the relationship between him and his dad hadn’t always been easy. “He raised me hard, and when I say hard, I mean hard,” Mark said. “I was taught to fight for everything and that the only way to go about getting something was with everything you had.”

What’s more, Tom apparently hadn’t spent a whole load of time at home with his family. “We missed a lot of time together,” Mark explained. And while when his father was around, they would play catch together – which Tom would often turn into a lesson. “He wanted me to work on control. When I threw a wild ball — which I inevitably did — my dad went into the house,” Mark said.

“[My father] wanted me to be self-motivated,” Mark went on. “He only saw me play football in high school once and didn’t watch again until two and a half years later at UCLA.” And Tom himself shared his thoughts on the matter to People. “I never spared the rod, and [Mark would] get whacked if he did something wrong,” he said. “But look at my kids now. They all know the difference between right and wrong, and there isn’t a druggie in the bunch.”

However, the relationship between Mark and Tom did improve. In 1972, you see, the 19-year-old Mark led his football team to a win against Nebraska – a team that had previously won 32 games in a row. And after the game, as Mark later told People, “I took off my uniform and started for the showers, and standing over at the far wall was my dad.”

“[Tom] had been there for two and a half hours, and he had not come into my cubicle,” Mark continued to People. “We locked eyes. He stood up straight and said to me, ‘Hey, great game!’ I burst into tears. Compliments from my dad never had been easy coming, and I reached out, and we hugged each other. From that moment, I knew my dad.”

Unfortunately, Tom passed away in 1990. The same day that he won a golf competition at the Bel Air Country Club, he had a heart attack. And while the sporting legend was rushed to the UCLA Medical Center, it was too late; he was declared dead while still at the emergency room. Tom was only 70 years old at the time, and Mark was just 38.

Image: Piyal Hosain/Fotos International/Getty Images

By this point, Mark had started to have children of his own. And he consciously decided to spend as much time with his kids as possible, even though work commitments called to him. “I left to do a movie in New Guinea, and our oldest had just taken his first steps the day I left,” he told CBS in 2013, referring to the 1991 film Till There Was You.

“And I came back three months later, and [my child] got out of the car by himself and walked up the sidewalk and grabbed onto my leg at the airport,” Mark continued. The toddler he was referring to is his son Sean Thomas Harmon – note the middle name – who is his first child with wife Dawber.

After Sean had grabbed onto his leg, though, Mark seemingly made a decision. The star later told CBS, “I turned to my wife, and I said, ‘[I] hate to tell you, but I’m not gonna be doing new movies in New Guinea for the rest of my life to be able to afford the house we’re in and miss all this.” Instead, Mark was going to focus on being there for his family.

Today, the Harmon children are grown adults. Sean followed in his father’s footsteps and became an actor – with a part on NCIS no less. Yes, when a younger Gibbs shows up in flashbacks, that’s Sean in the role. He’s also appeared on NCIS: Los Angeles and CSI. And Ty, Mark’s second child with Dawber, is a screenwriter.

Despite Mark’s successful home life, however, he has faced more sadness in the years since his father died. In 2012 his mother, Elyse, passed away at the age of 94. Then a few years after that, in 2018, his sister Kristin succumbed to a heart attack. Mark had earlier entered into an infamous legal battle with his sibling over the custody of her son.

You see, Kristin had experienced drug problems during her life, which had only intensified after her husband, Rick Nelson, had passed away in an airplane crash in 1985. Then, in 1987, Mark sued Kristin for custody of her youngest son, Sam. He claimed that the boy, who was then aged 12, was unhappy with his mother and needed to be placed in a better environment.

Meanwhile, Kristin claimed to People in 1987 that she had cracked under the pressure of being in a famous family. Her relatives, she asserted, had wanted her to be “a perfect person.” And she apparently didn’t get along with her mother, either, as she revealed, “I never cared much about being on the covers of magazines; [my mom] did.” Kristin was once close with Mark, however.

“I tried telling my family, ‘There’s a drug problem here, and we’ve all got to help.’ But they totally denied there was anything wrong,” Kristin told People. And indeed the magazine’s writer remembered – and featured in his story – Tom’s “there isn’t a druggie in the bunch” quote from two years prior.

In the end, though, the feud was resolved about as amicably as it could have been. Mark apparently made the first move by contacting Kristin’s attorney. Then an agreement was reached: Kristin got to keep custody of Sam, while Mark got visiting rights. Perhaps unsurprisingly, therapy was mandated for all three of them, too.

And nearly two decades on from Kristin’s chat with People, the adult Sam spoke out about his relationship with his mother in a 2016 interview with Medium. “As you get older, things that were important aren’t important anymore. Problems aren’t problems anymore,” he said. “You work through them, or you don’t. But for the most part, you hope to. I think we’re in a good way together.”

Image: Ron Galella, Ltd./WireImage/Getty Images

In the same interview, Sam spoke about Tom, his famous grandad. “I lived with my grandparents on the Harmon side during my parents’ divorce,” he said. “My grandfather passed away in 1990 of a massive heart attack. It was especially difficult to lose him, as he was a father figure to me.”

But despite having been in the public eye for years, Mark doesn’t talk about his personal life much. He didn’t speak about Kristin’s death to the media, for one thing; he also doesn’t use social media. “I’m not a Twitter guy or a Facebook guy. Our sons aren’t into that, either. Pam and I have both made a living in this business, and still, there’s a part of that that’s just not natural,” he told TV Insider in 2017.

However, in February 2019 Mark offered fans a rare in-depth insight into his private life. And touchingly, he revealed that he had spent his whole career following the advice of his father. “My dad taught me, ‘If it’s not true, don’t worry about it,’” the actor told People. Those are wise words for anyone in the media spotlight.

Image: John Bryson/The LIFE Images Collection/Getty Images

There were other things that Tom had taught his son, too, including the importance of hard work and perseverance. “I come from working stock, and I’m proud of that. You have to get up every day and just try hard,” Mark said to People. “That’s what I still wake up willing to do: try my hardest.”

Image: Ron Galella/WireImage/Getty Images

Plus, Mark shared yet some more of his father’s advice with the magazine. “Work your a** off, and don’t let the effort show,” he said. “Also, treat people the same – not based on who they are or what they are. Show them common kindness. Don’t be colored by their fame or profession. I don’t get all excited by people blowing smoke up my a**. You have to stay honest.”

Image: John Bryson/The LIFE Images Collection/Getty Images

And it’s fair to say that Tom’s blunt advice appears to have rubbed off on Mark. “You can tell me I can’t do something, but I’m likely to take that as incentive to prove you wrong,” the actor explained to People. “I’m a jock, so you can yell at me all day long, and that won’t hurt me. I’m just going to try to get better.”

Plus, on a lighter note, Mark also revealed his thoughts about being named the magazine’s Sexiest Man Alive back in 1986. And as it turns out, he was never too bothered about the accolade. “Oh, it isn’t that I hate it, really,” he said. “It’s just that I’m not about to take it seriously. And let’s just say I think maybe a few too many people have.”

Then, at the end of the interview, the NCIS actor dispensed some advice himself. “This choice – this career – requires you to be all in,” he said of acting. “Your job is to be prepared for the opportunity. It will come; you just won’t know when. So, until then, all you can do is invest in yourself.”

Image: Ron Galella/WireImage/Getty Images

“I’ve always worked hard, [and] I’ve always tried to pay attention to the little things, but here’s the real secret: there are no little things,” Mark went on. And when the magazine pointed out just how long the actor’s career in Hollywood had lasted, he said, “I’m a lucky guy, but you earn luck.”

And Mark’s luck shows no sign of going away any time soon, either. After all, NCIS is still a massively popular show. Even though the drama has been running for 16 seasons now, it still pulls in around 12 million viewers every week. Not only that, but the series has since spawned two spinoff shows: NCIS: Los Angeles and NCIS: New Orleans. It’s an unstoppable TV juggernaut, it seems.

And Mark’s role as Gibbs is so tied to the success of NCIS that he almost certainly won’t ever leave the show, and he has said as much to the media. Mark and Gibbs have a lot in common, too. For one thing, Gibbs’ father, Jackson – who was played by late actor Ralph Waite – was a World War II fighter pilot just like Tom Harmon was.