With the addition of the Las Vegas franchise, the National Hockey League will have 31 teams.
Principal owner Bill Foley, a Las Vegas businessman, and his partners will pay a $500 million expansion fee for the franchise.
"The first thing we're going to do is to establish what the culture is going to be for this team," Foley said. "This team is going to be a team built to win. We're going to take care of our hockey players in every way possible."
The team doesn't have a name yet. Foley, a graduate of West Point, said he loves the nickname of his alma mater, the Army Black Knights. But the team will work with the league to consider several ideas for names, he said.
Foley said he hopes to have a name by the time the NHL season starts in the fall so the franchise can begin to sell jerseys and other merchandise.
The yet-to-be-named team will play at the new T-Mobile Arena, which will have 17,368 seats for hockey. More than 14,000 people have put down season ticket deposits, a factor Bettman said helped Las Vegas' expansion bid.
The commissioner described Las Vegas as "vibrant, growing and a global destination."
"We think this is a tremendously exciting opportunity, not just for Las Vegas, but for the league as well," he added.
Some observers have raised concerns about the effect that gambling may have on the integrity of pro sports played in Vegas. Bettman said fans likely will be able to bet on games played in the city, but "we don't worry about the integrity of our game."
The arena will host an NHL preseason game on October 7 between the Los Angeles Kings and the Dallas Stars.
The expansion is the first for the NHL since 2000, when the Columbus Blue Jackets and Minnesota Wild entered the league
Quebec City's bid for an expansion team was deferred, Bettman said. He cited the recent devaluation of the Canadian dollar, the league's geographic imbalance and the thought it would be best to bring only one team in right now as reasons for putting the decision on hold.
The Las Vegas team will play in the Pacific Division for the 2017-2018 season. It will select 30 players -- one from each opponent -- in an expansion draft next year. There was no word on where its minor league affiliate would play or when that team would begin operations.
Las Vegas is already home to several professional sports teams, including the 51s, a Class AAA baseball team; the Sin, an indoor football team; and two indoor soccer teams.
The city has also hosted many world championship boxing matches, mixed-martial arts fights, NASCAR races, a PGA Tour event and was once the home to a Canadian Football League team.