Finally, if you're watching the olympics, you've probably seen this runner, in a el the vision ad. He's only 12 but weighs 200 pounds. Watching him struggle, some viewers think he's being mocked. But... See More
Finally, if you're watching the olympics, you've probably seen this runner, in a el the vision ad. He's only 12 but weighs 200 pounds. Watching him struggle, some viewers think he's being mocked. But as abc's ron claiborne discovered, he's turning out to be a real inspiration, too. Reporter: Every olympics, it seems one commercial stands out. In 1984, it was "we love l.A. " In '88, the pole vaulting budweiser dog. Greatness -- Reporter: And now this year, there's this. Some how we've come to believe that greatness is a gift. Reserved for a chosen few. For prodigies. For superstars. Reporter: Instead of an elite athlete performing some superhuman feat, this ad shows a 12-year-old, 200-pound boy from ohio jogging alone. Greatness is not some rare dna strand. It's not some precious thing. Reporter: His name is nathan sorelle, and before he made this commercial, nathan says he didn't even like running. I just kind of put the hatred of running to the side, because it was just such an experience and so fun. Reporter: Fun, except for the one take when he got sick from the exertion. Out of breath, took a drink, my stomach started hurting and i went over to the side of the road and just let it go. Reporter: Something about this commercial, the image of the overweight kid struggling down a country road, struck a chord with millions around the world. Online messages supporting nathan poured in. Many from overweight people. "I'm headed out for a jog around the block there's nowhere to go but up." I love nathan. I hope he runs until he feels awesome about himself. Sort of offsets the idea that the only people who are great are this pinnacle of greatness. I like the idea that anyone can do something challenging in their daily life. Reporter: Not everyone likes the ad. Some says it exploits a chubby kid. But nathan and his family are happy with it, just the way it is. And while he mail never be an olympic athlete, he sails he's going to keep at it. And he'll keep inspiring others. Ron claiborne, abc news, new york.
This transcript has been automatically generated and may not be 100% accurate.