Missler elected to claim his winnings in a bulk payment of US$281,874,999 (AU$355,970,413), instead of opting for a larger amount dispersed over several payments.
"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", Missler said in a statement.
Mega Millions drawing. Given a recent Facebook post written by Missler, he was likely aware of his winnings last week.
Shane Missler, 20, of Port Richey, is the victor of Friday's drawing with the winning numbers 28 - 30- 39- 59 - 70 and the Mega Ball was 10.
Missler bought five lottery tickets at a 7-Eleven store in Pasco County, Florida earlier that day, according to the Daily Mail, using money he previously won from a scratch-off lottery ticket. Then the next morning he shared the news with his father as they drank coffee.More news: China's trade growth cools as barrier complaints rise
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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 nearly $282m (£205m).
A believer in the power of a positive mindset, Shane wasn't really surprised that he had won. "I look forward to the future".
The winning Mega Millions numbers were 28, 30, 39, 59, 70, and Mega Ball 10.
Missler quickly "retired" from his job at a local background screening company, his lawyer, Walt Blenner, said in the statement.
There was only one Mega Millions ticket sold that won a jackpot worth $450 million. The jackpot is the fourth-largest in Mega Millions history, and Missler is the sole victor. A Florida victor split a $414 million jackpot in 2014, previously the high mark for any ticket sold in the Sunshine State.