Russell won 11 NBA titles with the Celtics, the most by any player, over his 13 seasons with the team, ESPN reports.
Russell was also a five-time NBA Most Valuable Player and a 12-time NBA All-Star. He later became the first Black coach of a North American professional sports team.
Aside from his decorated career in the NBA, Russell was heavily involved in the Civil Rights Movement. He was awarded the the Presidential Medal of Freedom in 2010 for his work.
"Bill called out injustice with an unforgiving candor that he intended would disrupt the status quo," the statement on Russell's Twitter read. "We hope each one of us can find a new way to act or speak up with Bill's uncompromising, dignified and always constructive commitment to principal."
Several current Celtics players took to Twitter to honor the late legend including Jayson Tatum and Jaylen Brown.
According to the statement, Russell died peacefully in his sleep with his wife Jeannine by his side. Information about his memorial services will be announced at a later date.
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