In 1999, he agreed to a public ceremony at the Fleet Center — the successor to Boston Garden — for the 30th anniversary of his last championship team and his retirement as a player as well the second retirement of his number. The event was also a fund-raiser for the National Mentoring Partnership, whose programs he had helped develop as a board member.

“There are no other people’s kids in this country,” he told the crowd. “They’re the children of the nation, and I refuse to be at war with them. I’ll always do anything I can to make life better for a kid.”

He made commercials, signed autographs for serious collectors (for a fee) and delivered motivational speeches.

Russell married for the fourth time, to Jeannine Fiorito, in 2016. His first marriage, to Rose Swisher, ended in divorce, as did his second marriage, to Dorothy Anstett. His third wife, Marilyn Nault, died in 2009 at 59.

Russell had three children from his first marriage — William Jr., Jacob and Karen Kenyatta Russell. William Jr., known as Buddha, died in 2016 at 58. Russell’s brother, a playwright and screenwriter under the name Charlie L. Russell, died in 2013 at 81. Complete information on survivors was not immediately available.

Russell was uncompromising when it came to his principles. “There are two societies in this country, and I have to recognize it, to see life for what it is and not go stark, raving mad,” he told Sport magazine in 1963, referring to the racial divide. “I don’t work for acceptance. I am what I am. If you like it, that’s nice. If not, I couldn’t care less.”

He was also an immensely proud man.

“If you can take something to levels that very few other people can reach,” he told Sports Illustrated in 1999, “then what you’re doing becomes art.”