The ruling takes the U.S. a step closer to legal sports betting in numerous states, possibly even nationwide. Currently, the practice is legal only in select places such as Nevada, home to the gambling capital Las Vegas. While Nevada's Gaming Control board reported $4.8 billion in sports bets last year, the black market total is considered to be many times the legal market.
Americans wager "$150 billion illegally each year through off-shore, black market bookies," DraftKings CEO Jason Robins said in a statement. The fantasy sports company has nearly 10 million customers across the country. After the ruling, DraftKings announced plans to launch a mobile platform for sports betting to tap into the new market.
"States are now free to allow their residents to place mobile sports bets with licensed, trusted companies based in the U.S. and that pay taxes here," Robins said.
Shares of several casino companies moved higher following the ruling, including Caesars Entertainment, up 6 percent and Penn National Gaming, up 4 percent. Others gaining included MGM Resorts, Boyd Gaming and Churchill Downs. Wynn Resorts stock recaptured some of its losses from earlier in trading, down 1.9 percent on the day.
The VanEck Vectors Gaming ETF rose 2 percent, on pace for its best day since March 26, with Scientific Games and Caesars leading the fund, up 10 percent and 6 percent, respectively.
Industry analysts have said that dozens of states might legalize sports betting if they are not barred from doing so by the federal law. While awaiting Monday's ruling, seven 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.
WATCH: Draftkings CEO on Supreme Court decision
The most recent Summer Games in Rio de Janeiro was the first Olympics in 15 years where Americans could places bets, if you were in Nevada. The Rio Olympics drew "about half of average [NFL] Sunday game" in bets, Vice Fund senior portfolio manager Jordan Waldrep told CNBC, but that could quickly change for the Tokyo Olympics in 2020.
"The big events ... [are] what everyone's going to be paying attention to," Waldrep said. "What they really want is a situation where there's some unpredictability, like a great Australian swimmer going against a great U.S. swimmer. What the betting market needs is competitive events."
"Tokyo is trying to take advantage of it because there is going to be a massive influx of people," Waldrep added.
Multiple professional sports leagues, as well as the National Collegiate Athletic Association, were challenging the New Jersey law: Major League Baseball, the National Football League, the National Basketball Association and the National Hockey League.
"Today's decision by the United States Supreme Court will have profound effects on Major League Baseball," MLB said in a statement. "As each state considers whether to allow sports betting, we will continue to seek the proper protections for our sport, in partnership with other professional sports."
The ruling's implication for college sports is unclear, according to the NCAA. The organization said it is reviewing the decision.
"We will adjust sports wagering and championship policies to align with the direction from the court," NCAA chief legal officer Donald Remy said in a statement.
– Reuters contributed to this report.