As he skipped rope at a rapid pace and seemingly without effort at his condo’s gym, actor Beulah Koale, who plays rookie Junior Reigns on “Hawaii Five-0,” said his stunt double doesn’t get much of a workout on set.

“I prefer to do the stunts myself when it’s stuff I know I can do with my abilities,” said the lithe, muscular New Zealand native, 26, who made his debut on the CBS crime drama this season.

He lists some of the stunts he’ll perform himself: “Coming through doors, beating up another guy, jumping around rocks, spinning off trees — but not falling off buildings or out of cars,” which the ex-rugby player said he might have tried if it weren’t for advice from Alex O’Loughlin, who plays “Five-0” leader Steve McGarrett.

“Alex warned me. He’s pretty injured, banged up from eight years of doing stunts,” Koale said.

“He’s like my big brother; he took me under his wing. And what a great actor!”

The warmth and appreciation are mutual.

“Beulah is an extraordinary young man,” O’Loughlin wrote in an email. “He’s truly an instinctual actor with enough courage for everyone and an innate understanding of truth.”

On a personal level, O’Loughlin called Koale “an awesome guy. Generous, kind, funny and tough as nails. We hit it off from day one and our friendship has only gotten stronger.”

For Koale, being cast in the internationally popular “Five-0” in 2017 was the culmination of a breakthrough year that saw the release of his first Hollywood feature film, “Thank You for Your Service,” directed and written by Jason Hall, an Oscar nominee for writing “American Sniper.” Koale played the principal role of Tasuolo Aieti, a stoic American Samoan soldier who suffers debilitating memory loss in the Iraq war and struggles to cope at home.

The film was based on a nonfiction book of the same name by Pulitzer Prize-winning journalist David Finkel.

“Utterly riveting” is how Tribune News Service film critic Katie Walsh described Koale’s performance opposite Miles Teller, and the Los Angeles Times included the actor on its list of overlooked performances of the year.

To prepare for the role, Koale did extensive research on PTSD and drew on his own experience as the eldest of six children growing up in South Auckland.

“I come from, like, the ‘hood of New Zealand,” he said. “I had a dad; he left with another woman. I used a lot of my own demons — what I went through as a child — for the role of Aieti to tap into that darkness, bring out truth.”

At the same time, Koale said, because of the close-knit community and the loyal friends he made, “I’m really proud of where I come from.”

A typical Hawaii winter’s day of variable winds and weather, it was raining when Koale met with a reporter in a conference room of the luxury Kakaako high-rise where he lives with his fiancee, Georgia Otene, and their twin sons. When the sun emerged, however, he led the way outside.

“I never had any of this,” he said, gesturing with an open arm at the large swimming pool and immaculately landscaped terrace. His pleasure in being able to provide this for his children shone in his large, expressive eyes.

“They’re water babies, 1-year-old Isaac and Xavier,” he said, sitting on the edge of the pool and kicking his feet in the water. He appeared eager to dive in.

What does he do on his days off from “Five-0”?

“Wake up, feed the kids, help Mom with whatever Mom needs.”

A curtain of rain blew through and he shrugged it off.

Koale, whose film debut was as a gang member in “Manurewa,” which won an award as best short in the youth category at the 2010 Berlin Film Festival, attributes his success to consistency and hard work.

Originally, he wanted to be a rugby player.

“I never dreamed of being an actor; you were considered a wimp,” Koale said. So once he started acting, “I kept it a little quiet from the boys for a bit.”

He attended the Auckland University of Technology and considered a career as a personal trainer. When a drama teacher suggested he audition for “Manurewa,” he did it “just for fun” and wound up with a new professional goal.

After appearing in New Zealand television shows and films, Koale got the role in “Thank You for Your Service.” A few months after that film wrapped, he heard from Hall — “I call him my angel” — that he had recommended Koale to “Five-0” producer Peter Lenkov, who was seeking a Pacific islander to play Junior Reigns.

Koale was in Indonesia shooting his next film, the forthcoming “Niihau,” when he learned he’d got the “Five-0” job and had only about two weeks to prepare. (In the movie, based on real events, he plays one of the islanders who apprehended a Japanese pilot who crashed on Niihau after the Dec. 7, 1941, attack on Pearl Harbor.)

Luckily, having recently played a soldier in “Thank You for Your Service,” the character of Junior, a former Navy SEAL, felt natural, he said.

Koale and Canadian actress Meaghan Rath (“Being Human, “New Girl,”) joined Season 8 of “Five-0” last fall, replacing original cast members Daniel Dae Kim and Grace Park, who departed the show last summer in a salary dispute with CBS.

Koale likes Junior’s happy personality and enjoys the scenes in which his character flirts with fellow Five-0 rookie Tani Rey (Rath). It reminds him a little of how he met his fiancee.

“I met Georgia six years ago at a charity running event in New Zealand,” he said. “We ran and walked side by side the whole way but I thought she didn’t like me. She was my first-ever girlfriend.”

In addition to O’Loughlin’s mentorship and the warm welcome extended by the older actor to Koale and his family, the entire “Five-0” crew and cast feel “definitely like ohana,” he said.

“First time I got on set I did a haka (Maori warrior dance) for the whole crew to show respect, and I’ve got it back 10-fold.”

Koale, who is of Samoan and Tuvalese descent, said he was taught the Maori language and culture in school. Living in Hawaii, he added, he doesn’t have to work at Junior’s happiness.

“All you have to do is look to the mountain and the ocean and you’re good.”

Looking to the future, Koale is ambitious and said he is always on the lookout for film auditions. He credits Dwayne “The Rock” Johnson, who is also of Samoan descent, for making it easier for Polynesian actors to be considered for roles.

“There’s more diversity in Hollywood right now. The Rock and others kind of opened the door for us,” Koale said.

“My goal is to catch The Rock and beat him,” he said with a playful look. “I know that he knows someone’s coming for him.”

He laughed. “I’m very proud of what he’s done.”

No matter where his career takes him, Koale said he would like Hawaii to be home.

“My favorite thing is to drive to Sharks Cove on the North Shore.” After owning a series of cars that used to break down on a daily basis, he’s got a BMW. “I drive and pray, listen to music — Motown, country, vintage hip-hop — and I’m just thankful.”

Koale’s happiness felt infectious on a rainwashed day when, for a moment, everything sparkled in the sun.