Patty’s eldest son with late rock concert promoter Michael Tell is none other than Samwise himself, Hollywood actor Sean Astin. Sean was raised and adopted by Patty’s third husband, actor John Astin, best known for playing Gomez Addams in The Addams Family.

But before he played a hobbit in the Lord of the Rings film trilogy, Sean got his start in acting at 10 years old in a television movie called Please Don’t Hit Me, Mom, in which he starred across from his mother Patty. 

He then went on to star in The Goonies, during which he shared a heartwarming moment with his mother on set. In an interview with The Hollywood Reporter, Sean recalled one shot where he made a “heroic statement”. 

“And I turned and looked at her … and she just has this look of, not just pride, but mortal gratitude,” he recalled. “It was just a confluence of a lot of things. She was incredibly proud of me. And she didn’t have to say anything, she just hugged me.

Sean notably starred in all three of the Lord of the Rings films in the 2000s and went on to appear in hits like 50 First Dates and the wildly successful Netflix series, Stranger Things. 

Alongside acting, Sean has continued to honour Patty’s legacy as a mental health advocate after his mother suffered from bipolar disorder. Sean established the Patty Duke Mental Health Initiative following his mother’s death to support mental illness. 

As of 2026, Sean is still acting and is the president of SAG-AFTRA.

Patty welcomed her second son, Mackenzie Astin, with her husband John in 1973. Like his parents and half-brother Sean, Mackenzie has gone into acting . 

The 53-year-old is known for his roles in the 1994 film Iron Will, the ’80s sitcom The Facts of Life, and TV series such as The Magicians and Shonda Rhimes’ Scandal. Last year, he made a guest appearance on the hit medical drama The Pitt. 

“I had a lot of good fortune in that both my parents were successful long before I was born and my mother had an experience in her childhood where she was extremely successful,” Mackenzie told Page Six. 

He added: “That kind of robbed her of her childhood, which I think had a negative impact later on in her life and because she had gone through that experience, I was well aware that was a possibility.”

Mackenzie and Sean were both there to support their mother at her Hollywood Walk of Fame ceremony in 2004. 

Following her split from John in 1985, Patty went on to marry Michael Pearce in 1996 and they share an adopted son, Kevin, who was born in 1988. 

Little is known about Kevin, but he publicly joined his mother at a New York screening of her film Valley of the Dolls in 2000. 

Patty also became a stepmother to Michael’s two daughters from a previous relationship. She was married to Michael up until her death in 2016.