Shea found himself unexpectedly set on the path to the Olympic podium more than 15 years ago. In 2002, he lost his lower left leg in a wakeboarding accident at age 19. A ski rope wrapped around his ankle and mangled his leg. The next thing he knew he was waking up in the hospital, surrounded by family and friends.
"I had already looked down at the bed sheets at that point and seen they had amputated my leg," he said. "And I really didn't know at that time what kind of opportunities there were for any disabled persons or amputees — I had never met anybody."
But Shea had been a high school athlete, and within months was out doing sports again, including snowboarding.
At the same time, he battled alcohol and painkiller addiction. He said he had pain from the amputation that lasted two to three months, enough time to be weaned off the medication.
"But the doctors kept giving it to me and I kept taking it, and there was a vicious cycle that spiraled me down in this deep dark place," Shea said.
After several years of abusing drugs, he entered a rehabilitation center. Once he got sober, he committed himself to competing in snowboarding as part of his switch from "young adult life to being an adult."
In 2010, he was invited to compete in a national competition, and quickly climbed the snowboarding ranks. In 2011 and 2012, he brought home silver at the Winter X games for the snowboard cross. He has also won three World Championship medals.
He said since the Paralympics added snowboarding to the 2014 roster, the sport has exploded internationally.
"It went from 15 to 20 competitors and to 50, to 60 to now almost 90 competitors," Shea said. "The level of riding and progression in the sport, it's so close to what you would see on an able-bodied circuit, at least at the top level."
His 2014 silver medal win in Sochi, Japan, changed his life dramatically. He won endorsements and developed a career giving speeches around the country, allowing him to focus solely on training and competition.
Shea is one of only two winter Paralympians who call California home. The other, Jen Lee, lives in San Francisco and is on the U.S. ice hockey team.
Many Paralympians move to cold-weather states where they train, such as Colorado. After a stint in that state, Shea decided he wanted to live in Castaic, in Los Angeles County, with his fiancee and her two sons.
Originally, he had planned to call it quits after the Winter Paralympics so he could devote himself to being a husband and full-time dad. His current competition schedule takes him on the road for six months a year.
"But I enjoy sports so much and I’m still in the best shape of my life and competing in a high level, so I will compete in World Championships likely next year and possibly take up a summer sport," Shea said.