Haslam bought the team from Randy Lerner for $1 billion, and the owners voted 32-0 Tuesday to approve the deal.
Haslam was met with applause as he entered the room with the other team owners. Browns team president Mike Holmgren and incoming executive Joe Banner were not present at the meeting, according to NFL.com and NFL Network's Ian Rapoport.
"It's going to be a great situation for Cleveland, their fans, players, coaches and the National Football League," Atlanta Falcons owner Arthur Blank said, via Rapoport. "Cleveland does have a storied history. It's important to (return back to that). It's a great franchise, it's been a great franchise."
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Haslam and Lerner agreed to the sale in August just as training camp was opening. Haslam has said his mission is to bring winning football back to Cleveland; the Browns have made the playoffs once since returning to the NFL in 1999.
"I would never stand here and say we need to have 'X' number of wins, but we want to see a positive direction," Haslam said. "I think we want to see continued improvement and we want to see them play hard."
"The best advice I can give him is the best advice I got from Robert Kraft when I bought the team 11 years ago," Blank said. "That's, the same points of success, the same principles you bring in business apply in the NFL. You do run the risk of injury, you understand media exposure, but other than that, fans are your customers, players are associates and partners.
" ... I think Cleveland's in a very good place, and I'm sure he'll bring some good people to work with him. Jimmy seems to be focused, very committed, has a lot of energy, all the right things for Cleveland."
The Associated Press contributed to this report.