That was until a routine physical stopped him in his tracks. The physical revealed he had an aortic aneurysm near the left valve of his heart.
"I was shocked," said the Memphis Grizzlies small forward. "I had no symptoms of fatigue, shortness of breath."
Green had to have open heart surgery.
"Leading up to it was nerve-racking," he said. "I couldn't run. I couldn't touch a basketball. I couldn't get stressed out, it was tough."
As Green learned how doctors would open up his chest to repair his heart, he considered the possibility he may never play basketball again.
"The first couple of weeks after I was told, I really focused in on my career and what was next," said the basketball player. "I wanted to make sure if I wanted to come back, I was able to come back and play the same way I did before I left."
If that opportunity wasn't there, Green wanted to have a backup plan. So, he headed back to his college roots at Georgetown University, finished his degree and became the first person in his family to graduate from college.
Green's NBA basketball career wasn't over, but it was a slow progression back to the court. He missed the entire 2011-2012 season.
"I didn't even watch any basketball," he said. "Six months after the surgery was the first time I set foot on a court."
It was with the Hoyas where Green laid back down the foundation of his game, healing his body and regaining muscle.
"The timing was off," he said. "I wasn't concerned about getting hit, the biggest thing was just being in shape and being able to move and being able to function on the floor."
Green believes the surgery and hard road back to the NBA have given him a new perspective and more meaning in his life.
"I will never forget those days that I could walk 15 steps for five minutes," he said. "Now I attack every game like this could be my last."
"I feel like the year I missed really added more years," he explained. "It added more life into what I'm doing because I'm more grateful for it."
Green's now using his story to raise awareness of hidden heart risk. He also spends time with children dealing with cardiac issues -- often telling them they are "superheroes" and encouraging them to "show off your scar -- embrace it!"