Newton, the 1979 Australian Open champion, died overnight due to "health complications", his family says.
Newton's Australian Open victory was one of three triumphs on the Australian tour - he also won once on the PGA Tour and was a three-time winner on the European Tour.
His golfing career ended prematurely in July 1983 when, aged 33, he lost his right arm and eye after walking into a plane's spinning propeller.
"(He) was a fearless competitor and iconic Australian, blazing a formidable trail during his professional golfing career between 1971 and 1983," his family said in a statement on Friday.
"He fought back from tremendous adversity as only he could.
"(He) chose to selflessly invest his time, energy, and effort towards giving back to the community through his Jack Newton Junior Golf Foundation, sports commentary, golf course design, and raising significant funds for several charities, most notably, diabetes.
"His passion for sport and contributing to future generations of golfers and the Australian community demonstrates the character of our father, beloved husband, proud brother, adoring grandfather, and maverick mate."
Newton is survived by his wife Jackie, daughter Kristie and son Clint. He has six grandchildren.
In July 1983, Newton's career was literally cut down in its prime when he lost his right arm and eye after walking into the spinning propeller while rushing madly to catch the Cessna 210 back home to Newcastle after watching a Sydney Swans game at the SCG.
Ironically, Newton would ordinarily have been in the UK playing the British Open, which he went so painfully close to winning eight years earlier if not for an arm injury that ruled the 1975 runner-up out.
But fate dealt Newton a cruel hand that rainy, wintry night which his great mate and former Australian prime minister Bob Hawke recalled at the 2015 Jack Newton Celebrity Classic in the Hunter Valley.
"I hadn't been prime minister long when the accident first happened and I of course went straight to the hospital," Hawke said.
"The doctor said: 'I don't know whether we're going to be able to save him PM but he's got two things going for him - he's unbelievably strong and he's got (wife) Jackie'.
"And those two things worked of course to save that marvellous life, which we're all terribly grateful for because he's been and continues to be a great Australian citizen.
"I always say at these meetings that I love Jack Newton. When I think of an Australian, I think of Jack Newton - courage unlimited, no bullshit, a thoroughly decent man who has dedicated his life which was saved in the most unusual of circumstances."
Jackie says it was a life that may not have been saved if not for her daughter's words in the devastating aftermath to the freak accident.
Concerned that Kristie and her two-year-old brother Clint would be too scared to see their father so horribly wounded, Jackie held back taking the children to the hospital for as long as she could.
Beforehand, she explained to Kristie that her father had lost an arm.
"Will daddy still be able to hug me?" Kristie asked, to which her mother said: 'daddy can cuddle with one arm'.
"The kids hardly noticed all the tubes, they were just so happy to see him and that it was just the thing that Jack needed to live."
Almost 40 years on and Newton was diagnosed with dementia.
Last December, the 42nd annual "Jacks" was the first since the shattering news was made public two months prior and the first since his son Clint, the former NRL star and now RLPA boss, replaced Newton on the board.
A who's who of Australian sports stars, musicians, comedians and dignitaries flocked to Newton's home town of Cessnock for the occasion.
The event has raised more than $3 million for charity over the years, while the Jack Newton Junior Golf Foundation has raked in upwards of $20 million for the development of the country's brightest young golfers since its establishment in 1986.
"Jack and I never started the Jack Newton Junior Golf with the mindset of generating such a significant amount towards golf," Jackie Newton said at the time.
"Jack simply loved the game of golf and we wanted to help children. To be in a position today, where we're now talking about these types of figures is truly incredible.
"We would both agree that this is arguably Jack's single biggest achievement in golf because it has impacted so many children and families over 35 years."
Still, Newton's on-course feats should never be forgotten.
He was a giant of the game when tragedy struck - just a year older than Adam Scott was when he won the Masters, and already runner-up at both Augusta National and the British Open.
In fact, Newton would have raised the Claret Jug at Carnoustie in 1975 had Tom Watson not drained a 20-foot birdie putt on the last hole to force an 18-hole playoff.
Watson then fortuitously chipped in for eagle on the 14th hole of the playoff to ultimately deny Newton by a shot and claim the first of his five Open trophies.
And it also took the wizardry of the great Seve Ballesteros to stop Newton from becoming the first Australian to don the Green Jacket at the 1980 Masters when the Australian finished tied for second place.