Scott Blumstein told reporters afterwards that it was "just the best feeling", but he was not motivated by the money.
Mr Blumstein, who has a degree in accounting, plays online poker for a living.
This was the first year he competed at the 120,995-person live tournament.
Each of the final nine men - who came from the US, France, the UK and Argentina - was guaranteed a $1m win at least.
As the winner, Mr Blumstein also walked away with a bracelet of gold and precious gems, which spells out WSOP and the images of playing cards.
Mr Blumstein said: "I'm still in shock. I thought I would get even more emotional ... but it's just the best feeling, I can't even put it into words."
A granddad from East Yorkshire in England won $2m by coming fourth in the series on Saturday.
A 25-year-old from New Jersey has won $8.1m (Â£6.2m) and become the world poker champion at the World Series of Poker in Las Vegas.