Karen Grassle had the perfect role model to play Caroline Ingalls on her classic show Little House on the Prairie.

“I based her on my mother,” Karen, 78, exclusively tells Closer. “If you read [Laura Ingalls Wilder’s] books and see photos, Caroline was very tough and sturdy. My mother rode a horse barefoot to school, and as a young woman, she taught in a one-room schoolhouse! So I took her character, strength and wisdom and infused Caroline with that.”

Those qualities also came in handy when she adopted son Zachary, 35, co-wrote and starred in the 1978 TV movie Battered to help abused women, and carved out an acting career that’s lasted more than five decades.

Closer talked with Karen about her childhood, her favorite Little House moments and why she has “so much to be grateful for.” Keep scrolling below to read Closer‘s exclusive Q&A!

little house on the prairie karen grassle michael landon

Everyone loves you from Little House, which you starred in from 1974–’82. How did you get the part?

I had spent a year in England, working with a Shakespeare company and teaching, and came back to the States flat broke. I was asked to fly to L.A. to play the lead in an independent movie, but when I got to the airport, there was no ticket! I’d sublet my apartment and my boyfriend was [with me], so I wrote a bad check to get one! But when I got to L.A., the movie fell through….

Oh, no! Did Little House save you?

My agent sent me up for a series with this guy from Bonanza [Michael Landon]. I was not a big TV watcher, so I asked, “Which one is he?” He said, “He’s Little Joe.” I was the only one at the interview — they’d seen everyone in Hollywood who was right for the part! They were down to the wire because they cast everyone else. After I read my second scene with Mike, he leapt up like a jack-in-the-box and said, “Bring her to wardrobe!” But NBC had to approve me, so he interviewed me for executives on closed-circuit TV.

What was Michael like on the set?

He was constantly trying to make the crew laugh and make everybody happy. A very hard worker, and he could be quite moody — he had a lot on his shoulders that first year. He had a falling-out with a producer very early on, so he was the only captain.

Which kid actor was most like their role?

The two Melissas [Gilbert and Sue Anderson] were unbelievably well cast. The kids were all really good. They say they didn’t miss anything in their childhood, but I say they don’t know what they missed because they were on the set.

What comes to mind when I mention Melissa Gilbert?

She arrived cute as a button and sharp as a tack for the pilot. Turned out to be a natural, with great instincts for acting.

…and how about Michael Landon?

Prodigiously talented. A complicated character from a dysfunctional family who loved his crew. But when the show was in the top 10 and I said, “Gee, it is time to renegotiate my contract,” Michael did not want to pay me. It was very difficult.

You’ve spoken about some pay inequities on the show. Did that cost you roles?

I didn’t speak up publicly at the time. Unless the fact that I continued to negotiate meant that Mike might have said things about me that could have been detrimental…. [But] we had a friendly call about the good old days [before he died in 1991]. I was glad we had that healing.

Were you typecast after the show?

Yeah, a lot of scripts were sent to me with people who wore a bun. [Laughs] I did [have trouble getting roles after], but my priorities shifted because I wanted to have a family, so I was putting less energy into acting than I was into figuring out how to be a stepmom and have a child.

Still, you did some fine work with Dennis Weaver in the 1983 TV movie Cocaine: One Man’s Seduction, and co-wrote and starred in the 1978 TV film Battered.

We were rewriting right up to the time we shot some scenes, but Mike Farrell rolled with it and was wonderful. He’s stood for many of the causes I believe in, like abolishing the death penalty. And he’s so attractive!

Any top showbiz moment?

When we worked with Johnny Cash and his wife, June, on Little House. I had been listening to his music since I was a kid!

What was your childhood like?

I was born just three miles from where I live now, in a small town called Albany [California] during World War II. We moved to Ventura by the time I was in first grade. My sister and I rode bikes to the beach, or went up a few blocks into the hills. My parents would go, “You have no idea [how good this is].”

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You were married to Leon Russom in the late ’60s, James Alan Radford in the mid ’80s and Dr. Scott Sutherland in the ’90s. What did you learn from those relationships?

I couldn’t possibly tell you that. But I called Alan yesterday because I heard he wasn’t feeling well. I just came across this beautiful butterfly box given to me by my three stepchildren many years ago. It was so touching. He helped them pick it out.

Why did you two adopt Zachary?

We wanted to have a child and we’d been having some difficulties. We were on the verge of beginning fertility treatment and started contacting people we knew about adoption. A friend said, “You have to call this woman.” She referred me to her [adoption] attorney [who knew of ] a young woman looking for a couple to adopt her child. It really felt like destiny.

Could you compare yourself and Mrs. Ingalls as moms?

I would fall very short! That show was an idealized version of family life. But I did the best I could. Much of the time I was a single mom, and that has its own challenges, [yet] I love so much about being a mom.

You have the lead role in an upcoming indie drama, Not to Forget. What’s next?

The musical that I was going to do this summer, A Little Night Music, just got canceled, but it’s not a tragedy. In about a year my memoir will come out, and maybe there’ll be some untold stories in there!

— Reporting by Amanda Champagne Meadows