"It's important to me to give back because I was a given a second chance, and I wasn't going to ruin that chance," Anthony "Doc" Ameen tells PEOPLE

For years after he lost his left leg to an IED explosion in Afghanistan while running to rescue a wounded Marine, Anthony “Doc” Ameen lived with an open wound on his remaining leg as a constant reminder of the horror he experienced on July 21, 2008, in the Battle of Nowzad.

The Navy hospital corpsman eventually received a prosthetic limb, which he wore proudly. But he always tried to hide the gaping hole in his right leg, worried what others would think if they saw the wound that had refused to heal and seemed untreatable after multiple surgeries.

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Then this past summer, the Phoenix-based founder of Wings for Warriors, a nonprofit that provides benefits guidance and counseling for wounded soldiers and travel assistance for their families, received a call from Florida’s Restoring Heroes Foundation, a charity that partners military veterans and first-responders with physicians to help heal traumatic burns, injuries and scars.

The group’s co-founder, Carol Novak, wondered if Ameen might know of a wounded soldier in need of orthopedic surgery.

“I said, ‘Are you okay with working with the founder of Wings for Warriors?’ ” Ameen, 36, tells PEOPLE, “and the rest is history. I flew to Florida and they closed off my infection and healed my leg, using a flap of skin from my thigh. I’m so grateful for what they did — it’s made a huge difference in my life. The hope is that I’ll never have to endure another surgery again.”

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The married father of four, who works fulltime for his nonprofit, is now racing after his 17-month-old toddler, Vance (he is also dad to Madelyn, 11, Laycie, 10, and Vivian, 4), and is preparing to take his first hike in almost 10 years.

“With all the tragedy and loss he’s experienced, it really is awe-inspiring, the way he continues to move forward in life,” says Ameen’s wife, Stephanie, 35, who works as a real estate agent. “He’s not only an American hero, he’s selfless, romantic and generous to those less fortunate and has such a huge heart. He goes out of his way to be there for veterans who are struggling and has compassion for families that are hurting.”

As a Navy medic, Ameen put that compassion to good use in Afghanistan during his first deployment, where his job was to provide on-scene emergency treatment to wounded soldiers.

Image zoom Anthony Ameen

On the day he lost his leg, his unit was setting up a Taliban ambush when they were counter-attacked. While rushing to help Lance Corporal Ivan Wilson, 20 yards away, Ameen stepped on an IED and immediately lost his left foot. He and Wilson were taken to a nearby medical unit, where doctors first worked furiously on Wilson, but couldn’t save him.

“I was screaming in pain, and then I woke up and my left leg was a stump wrapped in gauze,” Ameen tells PEOPLE. “I knew that my life would never be the same.”

After months of physical therapy to learn to walk with a prosthetic leg, Ameen spent two years fighting to get Social Security benefits and finally secured regular payments.

“Suddenly, guys started coming to me left and right to secure their own benefits,” he recalls, “and by December 2010, I decided I wanted to get back into the groove and do something positive with my time. I told my dad that our wounded warriors weren’t getting the benefits they deserved and he said that I needed to do something about it. So I did.”

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Wings for Warriors is now operating in 27 cities nationwide, with more than 2,500 veterans receiving help with health care and financial benefits, and more than 300 military families getting travel assistance to be with wounded loved ones.