He was part of the University of San Francisco team with Bill Russell that won back-to-back national championships in 1955 and 1956.
Russell tweeted condolences to the Jones family and shared a picture of the two.
I just received a call letting me know my x-roommate/teammate & most of all friend the great KC Jones passed this morning. Prayers to his family. We have been friends for almost 60yrs, this our last photo together. Friends for life #2020Usuck! #RIP @NBA @celtics pic.twitter.com/Ia6yZB5l2x— TheBillRussell (@RealBillRussell) December 25, 2020
Jones played nine seasons in the NBA, all with the Celtics, and won titles in eight of them -- the third most in league history, behind only longtime teammates Bill Russell (11) and Sam Jones (10). That success carried over to his coaching days, when he won three titles (one as an assistant, two as a head coach) during Boston's run of success in the 1980s with Larry Bird & Co.
Jones is one of only seven players to win an NCAA title, NBA title and Olympic Gold Medal.
"The Celtics family mourns his loss, as we celebrate his remarkable career and life," the Celtics said in a statement.
ESPN contributed to this report