"Oh. My. God." was the response of 20-year-old Shane Missler on Facebook after he bagged a $451m (£328m) Mega Millions lottery jackpot.
Instead of taking the full prize across several payments over a period of time, the Florida resident opted to receive a one-time payment of almost $282m (£205m).
Lottery officials said the win came after the man, from Port Richey, had five winning numbers and a mega ball number drawn on 5 January.
Florida Lottery said it was the fourth largest Mega Millions win in history.
Since his win, Mr Missler posted a photo of a book by businessman Gary Vaynerchuk he appeared to be reading, and added: Young entrepreneur in the making.
He later tweeted: The power of positive thinking should not be underestimated!
The winner told Lottery organisers he believed in the power of a positive mindset and that he was not surprised he had won. He said he had a feeling that he might.
His brother was the first person he called after receiving the news. He later told his father the following morning over a coffee.
Mr Missler said: I’m only 20, but I hope to use it to pursue a variety of passions, help my family and do some good for humanity.
The man, who worked as a verification specialist at a background screening firm – according to his Facebook – told the Tampa Bay Times he was going to take care of his family.
Although I’m young, I’ve had a crash course this week in financial management and I feel so fortunate to have this incredible wealth and team behind me, he said.
I intend to take care of my family, have some fun along the way and cement a path for financial success so that I can leave a legacy far into the future.