He became the first Black coach in the NBA when he served as player-coach of the Celtics in 1966 and the first Black player inducted into the Basketball Hall of Fame in 1975.
Bill Russell, the cornerstone of a Boston Celtics dynasty that won 11 NBA titles and a powerful voice for social justice, has died at the age of 88.
"Bill Russell, the most prolific winner in American sports history, passed away peacefully today at age 88, with his wife, Jeannine, by his side," said a statement posted on Russell's Twitter page on Sunday.
US President Joe Biden and former President Barack Obama — who awarded Russell the Presidential Medal of Freedom in 2011 — were among those who paid tribute to Russell's contributions on and off the court.
"The promise of America is that we are all created equal and deserve to be treated equally throughout our lives," Biden said in a statement. "We've never fully lived up to that promise, but Bill Russell made sure we never walked away from it."
Russell's 11 titles with the Celtics included eight in a row from 1959-1966. Today's NBA Finals MVP award is named for him.
He averaged 15.1 points and 22.5 rebounds per game for his career, building a famed rivalry with Wilt Chamberlain in the 1960s.
World 'lost a giant'
Russell's family said his "understanding of the struggle is what illuminated his life."
"Bill called out injustice with an unforgiving candor that he intended would disrupt the status quo, and with a powerful example that, though never his humble intention, will forever inspire teamwork, selflessness and thoughtful change."
Obama said the world had "lost a giant."
"On the court, he was the greatest champion in basketball history. Off of it, he was a civil rights trailblazer, marching with Dr. King and standing with Muhammad Ali," Obama said in a statement posted on Twitter.
NBA Commissioner Adam Silver called Russell "the greatest champion in all of team sports," but added that his accolades "only begin to tell the story of Bill's immense impact on our league and broader society.
"Bill stood for something much bigger than sports: the values of equality, respect and inclusion that he stamped into the DNA of our league," Silver said.
Michael Jordan, who for many inherited the mantle of greatest ever NBA player from Russell, said Russell "paved the way and set an example for every Black player who came into the league after him, including me.
"The world has lost a legend," Jordan said, a comment echoed by former New York Knicks great Patrick Ewing.