Three generations’ stories come together in actor’s converted garage.

As soon as Will Yun Lee saw the garage of his Tarzana home, he knew it wasn’t meant for a car but for a greater purpose — a taekwondo studio that’s an homage to his father, therapy for his son, and a confluence of his family’s past and future.

Three years ago, the actor and his family were moving out of their home in Sherman Oaks; at the same time, their then-3-year-old son landed in the ICU. He had been diagnosed with moyamoya, a rare disease that narrows the arteries supplying blood to the brain.

“We were desperate to find a house,” said Lee, who plays Dr. Alex Park on ABC’s “The Good Doctor”and also returns for the second season of the futuristic Netflix drama “Altered Carbon.” “This house had so many offers on it, but we wrote a letter to the prior owners and we got it. It was meant to be.”

Not least of all for the garage, which “became a very special room for us,” said Lee, 48.

“My son had had three big strokes. He’d lost a lot of mobility. I wanted to build something for him,” he said. “It became our martial arts space.”

The garage-turned-home-gym is as much a gift to Lee’s son Cash, now 6, as it is a tribute to his father, taekwondo grandmaster Soo Woong Lee, who was one of four taekwondo masters to emigrate from Korea to the United States in the 1960s. A marble-topped counter holds a framed photo of Lee’s father, taken back then with one of the country’s first African American taekwondo teams.

Starting in 1968, that Washington, D.C.-area team, the Simbas, dominated taekwondo competitions along the East Coast as the elder Lee instilled skills and discipline and his students rose above impoverished backgrounds and the racial strife of the time. The younger Lee recalled that history in “The Training Diary of Will Yun Lee” on YouTube, his chronicle of reconnecting with his martial arts background by re-earning his black belt from his father, who introduced him to the sport at age 3.

Now Lee wants to train Cash. The gym’s punching bags, shields and mats help the actor sharpen and maintain his skills. Meanwhile, Lee’s wife, actress Jennifer Birmingham Lee, uses the Peloton bike and elliptical machine, and Cash gets his own miniature stationary bike. The family dogs — labradoodle Kevin, Boston terrier Rusty and Shih Tzu Teddy, who otherwise roam free in the house — are not allowed, however.

Why is this your favorite room?

It has all the stuff I trained on when I was being taught by my dad. It’s where we hang out as a family. This is a place we can all enjoy together.

It’s especially important for you and Cash.

We’ve been doing physical therapy in here to help strengthen his legs. My wife and I have found ways to teach him in a way that holds his attention span, like doing lightsaber battles, or we’ll put on the gloves and have fun on the mat —little things to sneak in the physical therapy. He’s doing so great; looking at him, you’d never think he went through what he did.

How often are you in here?

We shoot both shows in Vancouver, so I fly in on a Friday, work out Saturday and Sunday, and then fly back. Martial arts has been a part of our family forever. I got into [UC] Berkeley on a fight scholarship. If I don’t do it I don’t feel balanced. That’s why I’ve wanted to teach my son, even though he’s had these challenges, that this is going to be a part of his life.

What was the design process?

Before I became an actor, I was running my dad’s taekwondo studios. When we were going to open our fourth location, this was the vision I had for it, this blackand-white simplicity. And my wife had the idea to put this special concrete finish on the cement floor. We wanted to keep it simple.

Has your father seen it?

He has. He was floored. There’s so much of our history here.