San Francisco, California - Don Nelson, the second-winningest coach in NBA history and a five-time champion as a player with the Boston Celtics, died on Sunday, his family announced. He was 86.

Nelson was a member of five NBA championship teams with Boston from 1966 to 1976, and the Celtics retired his jersey number 19.

As a coach, Nelson finished with a record of 1,335-1,063 – what had been an NBA record until Gregg Popovich passed him in 2022 – in stints with Golden State, Milwaukee, New York and Dallas from 1976 to 2010.

"Don Nelson revolutionized NBA basketball through his fearlessness, ingenuity and deep conviction," NBA commissioner Adam Silver said in a statement. "He spent nearly 50 years in the NBA – winning five championships as a player with the Boston Celtics before building one of the most successful and pioneering coaching careers in league history.

"He brought an unmistakable personality to everything he did, and his impact on our sport will continue to be felt for generations," Silva said.

Nelson, who was inducted into the Basketball Hall of Fame in 2012, never reached the NBA Finals as a coach but was remembered as a historic figure among bench bosses.

Los Angeles Lakers forward Luka Dončić posted on X about Nelson's death, writing, "It’s a sad day for basketball with the passing of Don Nelson. I have so much respect for him and everything he did for the game, especially the way he believed in international players.

"I’m grateful for the time I spent with him. Thinking of the entire Nelson family today. I loved getting to know you, Coach," Dončić wrote.

Steve Kerr, the current Warriors coach, recalled Nelson as a visionary whose influence remains within the modern NBA.

"Don Nelson was a true innovator whose influence on the game of basketball is still felt today," Kerr stated. "He consistently challenged conventional thinking, experimented with different lineups and styles of play, and saw possibilities in the game that others often did not."

"So much of what is now commonplace in the modern NBA can be traced back to the way Nellie approached the game," Kerr said.