American golf legend Arnold Palmer has died aged 87 in Pittsburgh.

Palmer claimed seven majors during his lengthy career, including four Masters titles, and he won 62 US PGA Tour events in total prior to retiring in 2006.

He died at UPMC Presbyterian Hospital in Pittsburgh, where he had been since Thursday while undergoing heart tests, but no cause of death was immediately given.

Palmer had looked frail when he joined fellow icons Gary Player and Jack Nicklaus for the ceremonial first tee shot at the Masters last April, when ill-health prevented him from swinging a club.

His Masters triumphs, played in front of his legion of fans known as “Arnie’s Army” who filled the galleries, came in 1958, 1960, 1962 and 1964.

He also lifted the trophy at the US Open in 1960 and the British Open in 1961 and 1962, while his best finish in the PGA Championship was a share of second place on three occasions.

Nicklaus was among a host of retired and current players who paid respect to Palmer and his contribution to the sport.

“Arnold transcended the game of golf. He was more than a golfer or even great golfer. He was an icon,” Nicklaus said.

“He was a legend. Arnold was someone who was a pioneer in his sport. He took the game from one level to a higher level, virtually by himself.

“We were great competitors who loved competing against each other, but we were always great friends along the way. He was the king of our sport and always will be.”

Arnold Palmer attends the ceremonial tee off to start the first round of the 2016 Masters Tournament. Photo: Getty

Tiger Woods took to social media to sing the praises of Palmer.

“Thanks Arnold for your friendship, counsel and a lot of laughs,” Woods tweeted.

“Your philanthropy and humility are part of your legend.”

Palmer won 92 tournaments across the world, including the 1966 Australian Open at the Royal Queensland Golf Club in Brisbane.

Nicknamed ‘The King’, Palmer was a dominant figure at Augusta National between 1958 and 1967, with his four victories coming amid a run of 10 straight top-10 finishes.

Thanks Arnold for your friendship, counsel and a lot of laughs. Your philanthropy and humility are part of your legend.

— Tiger Woods (@TigerWoods) September 26, 2016

Such sad news to hear about passing of #arnoldpalmer. Great memories of him. His legacy in the game & charity will live forever.

— Ernie Els (@TheBig_Easy) September 26, 2016

RIP #arnoldpalmer. You changed the game with your charisma and personality. Every player, me… https://t.co/RHuCgP6NCU

— Greg Norman (@SharkGregNorman) September 26, 2016

Born in Pittsburgh, Palmer learned the sport from his father, who was head professional at a local golf club.

His good looks, charisma and risk-taking play helped drive golf’s popularity on TV in the US, while his British Open victories boosted his reputation overseas and convinced several of his countrymen it was worth travelling to the United Kingdom for the tournament.

Palmer, fellow American Nicklaus and South African Player were golf’s ‘big three’ in the 1960s and many of their greatest battles took place on the fairways of the majors.

One of Palmer’s most famous victories came at the 1960 US Open at Cherry Hills Country Club in Colorado when he beat the then-amateur Nicklaus to win by two strokes.

He had trailed the leader Mike Souchak by seven shots at the start of the fourth and final round when he was tied for 15th place and considered no chance of winning.

I am so very sad to hear about the passing of Arnold Palmer, he was an amazing man! True legend. #The King

— Charl Schwartzel (@CA_Schwartzel) September 26, 2016

So much to say about Arnold Palmer on so many levels but too few characters here on Twitter to do him justice #RIP

— Paul McGinley (@mcginleygolf) September 26, 2016

Palmer ‘made golf sexy’

Palmer was one of 13 original inductees into the World Golf Hall of Fame in 1974.

He was also famous away from the golf course, with his name given to the internationally popular beverage consisting of iced tea and lemonade, which was a favourite of the burly golfer.

Although Palmer’s presence around the game had become less regular in recent years, today’s young stars were aware of the iconic player’s impact on their sport.

“Let’s be honest, it’s kind of a nerdy sport,” Australia’s world number one Jason Day said this year.

“Arnold Palmer made golf sexy.”

Palmer’s 62 US PGA Tour titles put him fifth on the all-time victory rankings and he led the tour money list four times, becoming the first player to win more than $US100,000 in a season.

He played on six Ryder Cup teams and was the winning captain twice.

Arnold Palmer lines up a putt during the Ryder Cup in 1973. Photo: Getty