The court upheld the legality of a 2014 New Jersey law permitting sports betting at casinos and racetracks in the state and voided the federal Professional and Amateur Sports Protection Act. Some states see sports betting, like lotteries, as a potentially important source of tax revenue.
The Supreme Court justices struck down the entire federal law on a 6-3 vote, with Justices Ruth Bader Ginsburg, Sonia Sotomayor and Stephen Breyer dissenting.
"The legalization of sports gambling requires an important policy choice, but the choice is not ours to make. Congress can regulate sports gambling directly, but if it elects not to do so, each state is free to act on its own," Justice Samuel Alito wrote in the majority opinion.
The state law at issue would allow people age 21 and above to bet on sports at New Jersey casinos and racetracks but would ban wagers on college teams based in or playing in the state.
"Today's ruling will finally allow for authorized facilities in New Jersey to take the same bets that are legal in other states in our country," New Jersey Gov. Phil Murphy said in a statement. "I look forward to working with the Legislature to enact a law authorizing and regulating sports betting in the very near future."
Allowing sports to legalize sports betting is great news for investors in both professional sports teams and the gambling industry, billionaire Mark Cuban told CNBC on "Squawk Alley."
"I think everyone who owns a top four professional sports team just basically saw the value of their team double," said Cuban, owner of the NBA's Dallas Mavericks.