The club made the official announcement Thursday, six days after a team official said it had reached an agreement to keep the star forward.
The Boston Herald had reported that the contract is for four years with Pierce and the Celtics having a mutual option for the fourth year. He had opted out of the final year of a contract for 2010-2011 that was to pay him $21.51 million next season. By re-signing for a lesser amount, which was not disclosed, he creates cap room and gets long-term security.
Since the Celtics lost the NBA finals in seven games to the Los Angeles Lakers, they've re-signed guard Ray Allen for the next two seasons and signed center-forward Jermaine O'Neal for the same period. Kevin Garnett also is signed through 2011-2012.