At 14-1 odds, the unidentified gambler's wager was turned into a $1,190,000 payout — the largest golf-related payout in the company's history.
“It’s great to see Tiger back," Nick Bogdanovich, director of trading at the U.S. office of William Hill, said. "It’s a painful day for William Hill — our biggest golf loss ever — but a great day for golf."
Woods' win on Sunday was his fifth-ever Masters victory, and his first since 2005. The 43-year-old shot a 2-under par 70 to win his 15th major championship.
It was his first major win since the 2008 U.S. Open, capping a remarkable recovery from debilitating injuries and embarrassing personal problems. He triumphed in the 2018 Tour Championship, which had been his first victory of any kind since 2013.
Additionally, Sunday's victory was the first time Woods has ever come from behind on the final day to win a major championship, leaving him three behind Jack Nicklaus' record of 18 major titles.
The Associated Press contributed to this report.