Andrew Karr’s story starts with his discovery of a child-sized boogie board in the garage of his grandparents’ summer house in Ocean City, N.J.

“Slick Lizard” was printed on that red piece of foam, which somehow launched one of the most remarkable careers in the wild world of big-wave bodyboarding.

A sport that’s supposed to be dominated by sun-soaked, beach-bred athletes from California or Hawaii has been turned upside down by Karr, a 22-year-old from Ambler who grew up 75 miles from the ocean in a landlocked state better known for woods than water.

“People are always saying to me, ‘Wait, where are you from?’” Karr said. “I say Pennsylvania and they go, ‘No way. You can’t be.’”

A former competitive swimmer at Germantown Academy, Karr over the last eight months has gone higher, dropped faster, and tunneled deeper — into the seemingly breathing heart of a big wave — than most followers of his sport believed possible for a bodyboarder.

Last October, Karr likely became the first bodyboarder to ride in the “barrel” of a big wave at the famous Jaws break in Maui, Hawaii, a feat caught on video by a stunned safety-patrol driver on a jet ski.

“The most exciting moment of my life,” Karr said of when he paddled into and caught a 30-foot wave at one of the most iconic surfing sites in the world. He rode inside that wall of water for five unforgettable seconds.

“I’m pretty sure he’s the first bodyboarder to accomplish that at Jaws," gaining ”a lot of international respect,” renowned big-wave surfer Kurt Rist said in an email. “When I saw the video, I couldn’t believe it. I was just like, ‘OMG, the kid did it.'”

In February, Karr was towed via jet ski by international big-wave surfing star Kai Lenny into the famous break at Nazare, Portugal, and rode a 60-foot wave, setting what is believed in the bodyboarding community to be a world record.

“He has put the bodyboarding world on notice,” Lenny said in an email.

Unlike surfers, bodyboarders ride waves prone on the board. Surfers stand on longer boards, which often have fins. Body boarders lay on their boards, which are shorter and lighter than surfboards, which allows the riders to more easily maneuver in the water but discourages many in the sport from trying to conquer big waves.

The sport sometimes is referred to as “boogie boarding,” after the brand name for the first bodyboards that hit the market in the early 1970s.

There’s nothing like riding big waves, said Karr.

“I love the fact that every part of your body and every part of your brain has to be 100% committed to it,” he said. “You feel so alert, so alive, even after you get out of the water.”

Karr is a philosophy major at Bates College in Lewiston, Maine. He took off the current school year to span the globe in pursuit of big waves.

He’s a Southeastern Pennsylvania guy who spent his summers in Ocean City. He binge-watched videos of big-wave surfers Laird Hamilton and Dave Kalama and grew “obsessed” with waves through high school, when he used to ditch class when powerful Nor’easter storms created sizable swells at the Jersey Shore.

“I used to make my mom drive me,” Karr said. “Then when I could drive, I would cut out of school at lunch just to get there.”

It’s a narrative that seems like it should be set in Hawaii or California, in some surfing community where the kids ride skateboards to the beach with surfboards balanced on their heads. But this was a suburban Philadelphia kid who was determined to take the big-wave world by storm.

“Andrew is the perfect example of, ‘If you put your mind to it, you can do it,’” Rist said. “Honestly, he could be one of the most positive human beings I know.”

Karr’s parents, Kirsten and David Karr, said they still wrestle with the push and pull of emotions: pride in his bravery and accomplishments, concern over his brazen willingness to take risks.

“It’s been really difficult at times,” Kirsten Karr said.

Added her husband: “There have been times when we’ve been like, ‘Oh my gosh, what is he doing?’”

Even Rist, known for his ability to ride massive waves in Ireland and elsewhere, tried to talk Karr out of his plan to bodyboard on some of the world’s biggest swells.

“He told me, ‘Kurt, I’m going to bodyboard Mavericks [a famous California break], Jaws, and Nazare,’” Rist said. “I said, ‘Bro, it’s literally not possible to bodyboard those waves.’

“I traveled the world. I’ve surfed most of these big-wave spots and I never saw a bodyboarder in the lineup.”

Lenny, who lives in Maui, said the bodyboarder from Southeastern Pennsylvania has been embraced by the big-wave community in Hawaii as much for his demeanor as his derring-do.

“For a guy who wants to push the sport into the most dangerous realm, he is a gentle soul, always funny and lighthearted,” Lenny said. “That goes a long way.”

Karr has been driven to excel at the sport since finding that board in his grandparents’ garage. He trained for years, developing the ability to hold his breath for nearly five minutes and riding breaks in Puerto Escondido in Mexico, Tres Palmas in Puerto Rico, and other world-famous spots for surfers.

Another secret to his success: uncanny poise under pressure.

“In heavy situations, he always kept calm, which is everything in big-wave surfing,” Rist said.

Karr’s feats in Hawaii and Portugal have changed his life, moving him closer to his dream of making a living as a big-wave bodyboarder. He has a few small sponsorships, and Red Bull energy drinks helped underwrite his trip to Nazare in February.

Karr shies away from the Association of Professional Bodyboard (APB) tour. Those competitions feature athletes with technical skills to perform twists, turns, and other tricks in the course of riding the wave.

Karr thinks of himself as a bodyboarding version of a free surfer, chasing big waves rather than specializing in acrobatics on smaller swells. He thinks there might be more broad-based interest in that aspect of the sport and more endorsement opportunities.

Still, no self-respecting, sun- and surf-worshiper would ever claim to be in the water for the money.

“For as long as I can remember, I’ve been drawn to the ocean,” Karr said. “It speaks to my soul.”