Westphal died after a battle with brain cancer, according to USC, where he played from 1969 to 1972. He was survived by his wife Cindy, two children and grandchildren.
Westphal was drafted by the Boston Celtics as the 10th pick of the 1972 NBA draft, according to USC. He won an NBA title with the Celtics in 1974.
After his playing career, Westphal started coaching, starting at several small colleges. His 1988 Grand Canyon College team won the NAIA national championship. He then moved to the NBA as an assistant coach with the Suns.
He spent 10 seasons as head coach for three different NBA teams, including the Suns – whom he coached to the 1993 NBA Finals – the SuperSonics and the Sacramento Kings.
“His toughness, skill and intellect made him a major contributor to the Boston Celtics’ 1974 championship team and an eternal All-Star at the Phoenix Suns,” said Silver.
“He will be remembered for his generosity, leadership and love of the game that shaped his many years in the NBA,” added Silver. “We offer our deepest condolences to Paul’s wife, Cindy, and their family.”
CNN’s Dakin Andone contributed to this report.