Who is Bill Chisholm, the man behind the record-setting $6 billion purchase of the Boston Celtics?

• Bill Chisholm, cofounder of private equity firm STG, paid $6.1 billion for the Boston Celtics.

• Chisholm is a lifelong Celtics fan from Massachusetts.

• The sale was the largest ever for a North American sports team.

After Bill Chisholm agreed to pay $6.1 billion on Thursday for the Boston Celtics, the NBA’s most storied franchise, Celtics fans — in nervous excitement — asked, “Who?”

Not only was it the highest price ever paid for an NBA team (the Phoenix Suns sold for $4 billion in 2022), it was the most paid for any North American sports franchise ever, and Chisholm’s name had never come up in earlier reports about interested parties.

Wyc Grousbeck, a member of the current ownership, Boston Basketball Partners, and the team’s governor, called Chisholm a “true Celtics fan” who is “totally committed” to the Boston community.

Chisholm cofounded STG, formerly known as Symphony Technology Group, in 2002 alongside Indian-American billionaire philanthropist Romesh Wadhwani, who is still chairman of the company, and investor Bryan Taylor, who is now a managing partner at Advent International after spending more than a decade at TPG.

STG focuses on investments in midsize enterprise software and technology companies, such as its $1.4 billion 2023 purchase of Avid Technologies, the manufacturer of media-editing software like Pro Tools, and its $1.5 billion purchase of SurveyMonkey creator Momentive that same year, as well as its creation of Trellix, a cybersecurity company that STG created by merging together McAfee’s enterprise business and FireEye.

The company rebranded to STG in 2017 and has owned 50 companies since its founding. According to its website, it had $10 billion in assets under management as of March 2023.

Chisholm is now the chief investment officer and managing partner at the company, where he runs the day-to-day management of STG companies, according to the firm’s website. The firm says he holds a bachelor’s degree from Dartmouth College and an MBA from The Wharton School at the University of Pennsylvania.

Boston Basketball Partners said in a press release that Chisholm is a lifelong Celtics fan and is native to the Boston area. The release said that Grousbeck would remain in his position and oversee team operations through the 2027-2028 basketball season if the deal is approved.

“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.”