Private equity mogul William Chisholm agreed to buy the Boston Celtics on Thursday in a deal that values the NBA's reigning champions and the most-decorated franchise in league history at a minimum of $6.1 billion US — the largest price ever for American professional sports team.

If the deal is approved by the NBA's board of governors this summer, the sale would top the $6.05 billion paid for the NFL's Washington Commanders in 2023.

A Massachusetts native and graduate of Dartmouth College and Penn's Wharton School of business, Chisholm is the managing partner of California-based Symphony Technology Group. The new ownership group also includes Boston businessmen Rob Hale, who is a current Celtics shareholder, and Bruce Beal Jr.

"Growing up on the North Shore and attending college in New England, I have been a die-hard Celtics fan my entire life," Chisholm said in a statement. "I understand how important the Celtics are to the city of Boston — the role the team plays in the community is different than any other city in the country. I also understand that there is a responsibility as a leader of the organization to the people of Boston, and I am up for this challenge."

Wyc Grousbeck, whose family leads the ownership group that bought the team in 2002 for $360 million, said Chisholm asked him to stay on as CEO and Governor for the next three seasons, "and I am glad to do so."

"Bill is a terrific person and a true Celtics fan, born and raised here in the Boston area," Grousbeck said. "His love for the team and the city of Boston, along with his chemistry with the rest of the Celtics leadership, make him a natural choice to be the next Governor and controlling owner of the team. I know he appreciates the importance of the Celtics and burns with a passion to win on the court while being totally committed to the community. Quite simply, he wants to be a great owner."

That would value the team at $7.3 billion. Sportico and ESPN were among those first reporting the agreement for the sale.

The record price for an NBA team was the $4 billion mortgage firm owner Mat Ishbia paid for the Phoenix Suns in 2023. But the Celtics are one of the league's flagship franchises, winning their unprecedented 18th NBA title last June and among the favorites to win again this season with young stars Jayson Tatum and Jaylen Brown — successors to a tradition of championship-winning Hall of Famers running from Bob Cousy to Bill Russell to Larry Bird to Paul Pierce.

Shortly after beating the Dallas Mavericks for the NBA title last summer, Grousbeck announced that the team would be put up for sale.

"My partners and I have immense respect for Wyc, the entire Grousbeck family and their indelible contributions to the Celtics organization over the last 23 years," Chisholm said. "We look forward to learning from Wyc and partnering with Brad Stevens, Joe Mazzulla and the talented team and staff to build upon their success as we work to bring more championships home to Boston."