Jose Luis Sanchez started working out for himself. Now he runs to inspire others. (Charles Krupa/Associated Press)

Retired Marine Staff Sergeant Jose Luis Sanchez didn’t intend to become a role model. He started working out just so he could feel like himself again after an encounter with an IED during a patrol of Afghanistan in 2011 left him with an amputated left leg and injured right calf.

“The injury humbled me,” Sanchez, a former high school football, basketball and track athlete, told GrindTV. “I lost all my muscle mass. I lost a ton of weight. I couldn’t walk or move or stand up. I needed assistance just to get out of my wheelchair, and even then I couldn’t walk more than a foot without collapsing. … I just wanted to work out to become the person I used to be.”

Six years later, Sanchez is inspiring millions by not only completing the Boston Marathon, but by running the 26.2 miles with the American flag his patrol unit signed and sent to the hospital years ago when he was still recovering.

“I boxed it up for three or four years because I didn’t want to acknowledge it,” the 33-year-old told Runner’s World on Monday.

When he finally unwrapped it in 2015, he also decided to uncloak himself in a way. Until then, Sanchez had been working out alone, always hiding his wounds when he went out.

“I didn’t want to hear that negativity,” the San Antonio native told GrindTV. “I felt ugly. Nobody wants to see those wounds, hell, I don’t even want to see them.”

But seeing that flag again, covered in inspirational quotes from his friends, lit a fire under him, he said, and gave him the motivation he needed to eschew any remaining negativity.

Sanchez began posting his workouts online, both to Instagram and Facebook, where he’s amassed more than 50,000 followers. Now with the world behind him, Sanchez, who told Runner’s World he doesn’t even like to run, decided to take on his biggest athletic challenge yet — the marathon.

Sanchez, who runs to raise money for the Semper Fi Fund, an organization that helps wounded veterans, has now completed three of the 26.2-mile events. He ran his first, the Marine Corps marathon in Washington, D.C., in 2015, before completing his inaugural Boston Marathon last year.

Carrying his now beloved flag each time, Sanchez’s time has steadily improved, too. He clocked in at 7:44:10 in the 2015 race, according to the official results. This year’s time in Boston was 5:46:13.

“I just woke up one day and said, ‘Hey, why not?” he recalled to Runner’s World about why he decided to start running long distance. “Let’s see what we can do today.”

Sanchez has no plans to scale his workouts back, and he sees more marathons in his future. The unwitting role model doesn’t just work out for himself anymore; he does it so that others might avoid feeling like he did when he first got wounded.

“I do this to inspire people,” he told Runner’s World. “It’s to inspire people to say yes to something they are afraid of.”