Inside the Tragic Downfall of Kristin Harmon: Mark Harmon's Late Sister and Former Member of TV Royalty

NCIS actor Mark Harmon’s sister, Kristin Harmon, died on April 27 at the age of 72 — and her life was anything but ordinary.

The late actress and painter’s daughter Tracy Nelson confirmed her mother’s passing on Facebook on May 1, writing in a post that Kristin “passed away suddenly and unexpectedly” of a heart attack.

A one-time golden girl, Kristin was born to football star and Heisman trophy winner Tom Harmon and actress Elyse Knox Harmon. She was the older sister of Mark, 66, and former model Kelly Harmon, 69.

When Kristin was 12, she met Ricky Nelson, who was the son of ’50s superstars Ozzie and Harriet and starred alongside his family on their long-running sitcom and radio show, The Adventures of Ozzie and Harriet. Kristin fell in love with their family and later, she fell in love with Ricky. She married him in 1963 when she was 18 years old and was thrust into the spotlight after appearing on the family’s show as Ozzie and Harriet’s real-life and TV daughter-in-law.

The couple’s first child, Tracy, was born six months after their marriage. As a pre-schooler, Tracy appeared in Yours, Mine, and Ours alongside Lucille Ball and went on to star in The Father Dowling Mysteries. In 1967, the Nelson’s twin sons Gunnar and Matthew were born and would eventually form their rock band, Nelson. Their fourth child, Sam, was born in 1974.

Kristin and Ricky seemed to be living their happily ever after — but soon, they got caught up in a lifestyle of partying.

“We were hippie rock ‘n’ rollers,” she said in a 1987 PEOPLE cover story. “We did what everyone else was doing all those years.”

“At first we were in it together,” she continued. “I tried to be one of the guys, to fix the marriage by going on the road and being involved in road stuff that is really not good for anyone. After a while we were totally messed up, both of us. I got into therapy and so did he for a while but then he started not showing up. 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.”

In 1980, Kristin filed for divorce and was temporarily granted custody of the children and spousal support. Accusations of drug and alcohol use and poor parenting were exchanged before the divorce was finalized in 1982.

During this time, Kristin said she continued to use drugs and to drink “quite heavily.” Since she was too drunk to paint for a living, she said she took a job as an assistant casting director at a salary of $200 a week. For two years before Kristin’s divorce, Kelly said she took care of Sam every afternoon and all day Saturday; and for the next 18 months, Sam lived with Kristin’s parents before moving into Mark’s home with his wife Pam Dawber.

Then in 1985, Ricky died along with his fiancée Helen Blair and five members of his road company in a plane crash while traveling to Texas. As Kristin continued to spiral, Mark stepped in and urged her to sign herself into rehab.

“Nobody but my brother could have talked me into this because I trusted him,” Kristin said. “A voice inside me said, ‘For once in your life, let somebody help you.’ ”

After her rehab stint, Kristin was informed in 1987 that Mark and Pam would be taking her to court to seek custody of her son Sam, who was just 12 at the time. At their hearing that July, Mark was awarded temporary custody of Sam. Kristin was ordered to stay 200 yards away from her brother’s house and from anywhere Pam was working.

During the increasingly vitriolic trial in August, there was mud-slinging by both sides. As contentious accusations flew, Mark finally approached Kristin’s attorney and said, “We don’t want to go any further with this. Too much blood has been spilled.”

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By the end of the day, the family had worked out an agreement in which Kristin retained custody, Mark was granted visiting rights and Kristin, Sam and Mark agreed to enter family therapy.

Sam went on to graduate from Boston College and formed his band H Is Orange. In a 2016 interview with Medium, Sam said that he and Kristin were “absolutely close” and that she was living in New Mexico.

“As you get older, things that were important aren’t important anymore,” he said. “Problems aren’t problems anymore. 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, and we have a good relationship.”