It might be a little bit of a stretch to call Dewitt Clinton a hero, but he certainly is very important in US history. If he is to be called a hero, it is because he was instrumental in the construction of the Erie Canal.
The Erie Canal was one of the most important projects in early American history. It was extremely important for the US economy because it tied the Great Lakes to the Atlantic Ocean. By making this connection, the canal allowed New York City to become hugely important. It also made transportation of goods much cheaper and allowed the US economy to grow.
Because he was so important in getting this vital project accomplished, Clinton could be seen as a hero.