TALLAHASSEE — About 1 a.m. Thursday, 20-year-old Shane Missler wrote on Twitter: "The power of positive thinking should not be underestimated!"

By that time he already knew he had won the lottery.

And not just any jackpot, but $451 million.

Missler bought five quick-pick Mega Millions tickets last week at a 7-Eleven store in Port Richey, where his family lives. One was the sole winner of the fourth-largest Mega Millions jackpot of all time, lottery officials said. Missler, grinning widely and clutching a yellow envelope, turned it in Friday shortly after noon at the Florida Lottery headquarters in Tallahassee.

He was with his dad and a lawyer, who released a statement on his behalf:

"If there is one thing I have learned thus far in my short time on this earth it is that those who maintain a positive mindset and stay true to themselves get rewarded," Missler said. "I look forward to the future."

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Missler — not even old enough to celebrate his winnings with a drink — opted to take the lump-sum payment of $281,874,999. The Florida Lottery withholds federal income taxes at a rate of 25 percent, officials said, dropping the amount to $211,406,249.25.

The Lottery shared in a statement that Missler "wasn't really surprised that he had won" because he had "a feeling" that he might.

About half an hour after the Jan. 5 drawing, he posted to Facebook: "Oh. My. God."

When he learned he had all the numbers right, he called his brother first, then told his father while they shared cups of coffee the next morning. Lottery officials said the money will be paid to a trust, set up with Missler as the managing member. It is called "Secret 007, LLC."

"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," Missler said in his statement to the Tampa Bay Times. "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."

The winning ticket was purchased the same day as the drawing from the 7-Eleven. The store, at 7131 Ridge Rd. in Pasco County, will receive a $100,000 commission.

Missler used money he won from a scratch-off lottery game to buy the Mega Millions tickets. The winning combination, 28, 30, 39, 59, 70 and the Mega Ball, 10, came on the fourth set of numbers.

Missler quickly "retired" from his job at a local background screening company, his lawyer, Walt Blenner, said in the statement.

The 20-year-old, whose social media accounts are full of references to New England, the Boston Celtics and the Patriots football team, plans to move away from the Tampa Bay area. His online presence is overwhelmingly uplifting, with inspirational quotes dotting a Twitter feed and the bio section of a sparsely updated Instagram account reading: "I wake up everyday saying 'Thank you' " and "Chase your dreams."

Late Friday afternoon, Missler tweeted once again: "Thank you everyone for the positive thoughts. This is only the beginning. I am truly grateful and most appreciative."

His family is originally from Maine.

Larry Thornton, who said he coached Missler on the soccer team at Spruce Mountain High School in Jay, Maine, recalled that even several years ago, the teen seemed mature among his peers and was a leader who made underclassmen feel welcome.

"He's going to find out what he needs to do and how he's going to do it," Thornton said in an interview Friday. "I can't see this going off the rails for somebody like him."

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Mega Millions is played in 44 states, Washington D.C. and the U.S. Virgin Islands. Last fall, administrators increased ticket prices and the starting jackpot, hoping to boost attention for the game around bigger winnings.

The largest Mega Millions jackpot of all time was $656 million in March 2012. Three winning tickets were sold, in Kansas, Illinois and Maryland. A Florida winner split a $414 million jackpot in 2014, previously the high mark for any ticket sold in the Sunshine State.

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Pasco County is no stranger to lottery fever. In 2013, an 84-year-old woman was the sole winner of a $590.5 million Powerball drawing — then the largest single jackpot in American lottery history. She bought her ticket at a local Publix and took the lump sum.

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Times staff writer Colleen Wright contributed to this report. Contact Zachary T. Sampson at zsampson@tampabay.com or (727) 893-8804. Follow @ZackSampson.