That's why most people including his opponents are shocked when they find out he's autistic.
Not too long ago doctors said Sean would have to be institutionalized.
"It was devastating for about ten seconds, and then I thought how could they possibly know that? They don't know him. They're giving him a life sentence at 6 years old," Sean's mother Eileen Coleman said.
While doctors were setting limitations, his parents were not. The sophomore is in mainstream classes and competing in just about every race in the pool and on the track.
When asked why he loves cross country, Sean replied, "Because I love to run through the woods."
Sean has come a long way in his everyday life and a long way out on the track, as in one season in cross country, he went from not being able to finish warm-ups to improving his time by 17 minutes.
"The day I saw him come out of the woods out of his first cross country race, my mind went to that diagnosis," Eileen said.
"Rounding that final turn and seeing his face, it brought tears to my eyes," Brandywine High School coach Michelle Flanagan said.
There were tears from mom and coach and one big smile from Sean like he always does when he finishes a race.
According to Sean his mom tells him, "Did you have fun? I'm so proud of you and good job."
Despite autism, Sean Coleman's life is on track.