Joe Asher, CEO of the U.S. arm of British bookmaking giant William Hill, said Tuesday he knows from personal experience about the ills of gambling.
"My dad was a gambler. He bet with his bookie. He bet too much. So for a small segment of the population, it becomes an issue," he said. "Certainly nobody stepped in and helped my dad when he needed help. I know that."
"The point is, I think, that's much more likely to happen in the legal, regulated market than it would ever happen in the black markets," said Asher, who became CEO of William Hill US after the company bought a gambling business he launched in 2008.
Anti-gambling organizations were critical. The high court ruling "will likely increase gambling participation and gambling problems unless steps are taken to minimize harm," said Marlene Warner, president of the National Council on Problem Gambling's board of directors. The council said any government body or sports league that receives a direct percentage or a portion of sports betting revenue should dedicate some of it to treat gambling problems.
For their part, all four major U.S. professional sports leagues — the NBA, NFL, NHL and MLB — as well as the NCAA opposed the ruling, saying a gambling expansion would hurt the integrity of their games.
However, Mark Cuban, billionaire owner of the Dallas Mavericks, said on CNBC on Monday he disagrees. "I think everyone who owns a top four professional sports team just basically saw the value of their team double."
The Supreme Court's decision on Monday was to uphold the legality of a 2014 New Jersey law permitting sports betting at casinos and racetracks in the state.
Ahead of Monday's ruling seven other states — Connecticut, Delaware, Pennsylvania, Iowa, New York, Mississippi and West Virginia — had laws prepared to make sports betting legal. Thirteen other states — California, Illinois, Indiana, Kansas, Kentucky, Maryland, Massachusetts, Minnesota, Michigan, Missouri, Oklahoma, Rhode Island and South Carolina — have plans or proposals to consider legalizing sports betting.
One of the first sports betting operations to open outside Nevada could be at Monmouth Park racetrack in New Jersey. William Hill US, already the biggest sportsbook in Nevada, invested in sports gambling at Monmouth Park five years ago.
"We always, of course, had an eye outside of the state [Nevada]," Asher told CNBC. "We made a bet back in 2013 on Monmouth Park in New Jersey. And obviously, it turned out to be a pretty good bet," said Asher, who added it could open for business with a few weeks.
Dennis Drazin — CEO Darby Development, operator of Monmouth Park — said on CNBC Tuesday the track needs a bit more time before launching.
"It takes a couple weeks to finish off the technology. We weren't sure which way the Supreme Court would rule. We were very confident of victory. But there were two paths. And we wanted to make sure we got it right," Drazin said.
Illegal sports betting in the U.S. has been estimated to generate as much as $400 billion per year. "[That's] where we think it is," he said, predicting a conversion into legal operations in New Jersey of about $10 billion annually.
— CNBC's Michael Sheetz and The Associated Press contributed to this report.