The British and Irish Lions international was described by the Welsh Rugby Union as “one of the greatest wings to play for Llanelli and Wales” after news emerged of his passing on Thursday morning, with Williams scoring 12 tries in 30 appearances for his national team.
Williams was part of the Wales teams who won Grand Slams in 1976 and 1978, which coincided with four consecutive Triple Crown triumphs between 1976 and 1979, but he remains best known for his try-scoring exploits with the Lions as a two-time tourist.
He scored four tries in the 1974 series against South Africa, becoming only the second man to score two tries twice in a Lions Test, while he also equalled David Duckham’s record of scoring six tries in a single match in the 97-0 warm-up victory over South West Districts.
He also scored in the 1977 series against the All Blacks, taking his overall haul to five tries that sits second only to Ireland’s Tony O’Reilly’s six tries in 1955 and 1959.
"We have lost a true legend of the game - RIP JJ Williams,” the Lions said in tribute to Williams. “A man who inspired a generation with his incredible running and finishing abilities.
"The Welsh winger was a key member of our famous 1974 and 1977 Tours, delivering commanding performances across seven Tests."
The WRU added: "JJ Williams, one of the greatest wings to play for Llanelli, Wales and the British & Irish Lions, has died at the age of 72.
"All our thoughts are with JJ's family and friends at this sad time."
Saturday will mark the 48th anniversary of Llanelli beating the All Blacks 9-3 at Stradey Park - a game in which JJ played - and the day will also see the town's Parc y Scarlets host Wales' Six Nations clash with Scotland.
The town's clubs lined up to pay tribute, with his former club Llanelli posting: "It is with great sadness that we hear of the passing of the great JJ Williams. We would like to extend our sincerest condolences to his family, friends and former teammates."
JJ Williams pictured with his son Rhys after claiming 400m hurdle bronze at the 2006 European Athletic Championships
Scarlets - the Pro14 club based in the town - tweeted: "We are deeply saddened to hear that our former player JJ Williams has passed away. JJ played 223 games for Llanelli RFC in nine seasons at Stradey Park. Our thoughts are with JJ's family, many friends and former teammates at this sad time. A true great of Welsh rugby."
Another of Williams' former clubs Bridgend Ravens tweeted: "All at Bridgend Ravens are deeply saddened to hear of the passing of former player JJ Williams. Our thoughts are with JJ's family and friends at this tough time."
Players, politicians and people from the entertainment industry were among those tweeting their respects following the news, with former Wales and Lions wing Shane Williams posting: "So sorry to hear that JJ Williams has passed away! It was a pleasure to have shared your jersey."
Additional reporting by PA