Celtics star Jaylen Brown is staying put in Boston for a while.

Brown and the Celtics have reportedly agreed to a five-year, $304 million supermax extension, the richest contract in NBA history. He officially signed the contract on Wednesday.

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“I appreciate the investment and commitment from the Celtics and the rest of the community,” Brown said. “That investment will be felt in return from me here in Boston, on and off the floor, and all around the world.”

It keeps Brown with the team that drafted him third overall in 2016 and watched him develop into a two-time All-Star.

He averaged career highs of 26.6 points, 6.9 rebounds and 3.5 assists last season. But those numbers went down in the playoffs, when the Celtics lost to the Miami Heat in the Eastern Conference finals. In Game 7, Brown had 19 points on 8-of-23 shooting, making just one of nine 3-point attempts.

Still, the totality of his time in Boston has made him a key piece of the franchise’s current core that management wasn’t willing to risk seeing depart when his current four-year deal expires after next season.

By virtue of making the All-NBA second team — Brown’s first such honor in his career — he was eligible for the supermax extension.

From the moment this past season ended, Celtics president of basketball operations Brad Stevens has been adamant that he wanted to see Brown sign a long-term deal.

“He’s a big part of us. We believe in him and I’m thankful for him,” Stevens said last month. “I’m really thankful that when those guys have success they come back to work. And when they get beat, they own it and they come back to work. And so I know that’s what they’re about. And that’s hard to find.”

Those sentiments were echoed by All-Star Jayson Tatum, who has paired with Brown to lead the Celtics’ one-two punch in their runs to the NBA Finals in 2021-22 and the conference finals last season.

Following Boston’s East Finals loss in May, Tatum said retaining Brown long-term was “extremely important.”

“He’s one of the best players in this league,” Tatum said. “He plays both ends of the ball and still is relatively young. And he’s accomplished a lot so far in his career. So, I think it’s extremely important.”

Brown’s new contract likely will lead to some financial maneuvering down the road with the league’s new collective bargaining agreement bringing more limitations on how teams construct their rosters and additional luxury tax penalties.

Tatum is still playing under his rookie extension that kicked in last season and will be eligible for his potential supermax extension next summer.

Information from The Associated Press was used in this report.