New Jersey has ushered in a new era of legal betting.
The state won a US Supreme Court case last month, potentially paving the way for all 50 states to allow sports betting.
Democratic Governor Phil Murphy, who is Irish American, marked the day by placing two 'flutters'.
The first official bets were made by the politician at Monmouth Park, a racetrack near the Jersey shore.
He placed two $20 wagers - one on Germany to win the soccer World Cup and another on the New Jersey Devils hockey team to win next year's Stanley Cup.
While most casinos have not yet announced whether they plan to introduce sports betting, Atlantic City's Borgata casino had said they would start taking bets half an hour after Gov. Murphy made the inaugural move.
"I'm thrilled to be doing it," Murphy told WFAN radio host Mike Francesca. "It's been a long time coming. Many, many years."
Other dignitaries including former state Senator Raymond Lesniak were also in attendance to make bets. The retired lawmaker spent years leading the state's push for legalizing sports betting.
New Jersey is now the third state to allow sports betting. Delaware enacted the law last week, and betting has always been legal in Nevada.
Legal sports betting means our casinos in @VisitAC and our racetracks can attract new business and new fans, creating jobs and strengthening the economy.— Governor Phil Murphy (@GovMurphy) June 14, 2018
Today at @BorgataAC, I saw the future of New Jersey gaming, and it is bright. pic.twitter.com/vv2O1t565e
The US Supreme Court case victory is the result of a near-decade long push and a $9 million fight to legalize sports betting as a way to boost the Garden State's stagnant casino industry.