Arnold Palmer, known as "the King" for his transformative legacy in golf, has died at the age of 87.

He died Sunday evening at a Pittsburgh hospital while awaiting cardiac surgery, according to a statement from his company.

With his dominance in golf and distinctive style, Palmer helped turn the sport from a country club pursuit to one that became accessible to the masses.

How Arnold Palmer changed golf

He won more than 90 golf tournaments, including the Masters four times, the U.S. Open in 1960, and the British Open in 1961 and 1962. Palmer became the first person to make $1 million playing golf.

"I would like to be remembered for bringing golf to a worldwide audience," he told CNN in 2012. "Players today have no boundaries."

He and his two great rivals in the "Big Three" -- Gary Player and Jack Nicklaus -- helped take the sport around the globe in the 1960s, capitalizing on the ever-growing reach of television. Golf grew into made-for-television events and with it came massive sponsorship and prize money. "He took the game from one level to a higher level, virtually by himself," wrote Nicklaus in a statement.

"Arnold always had my back, and I had his. We were always there for each other. That never changed. He was the king of our sport and always will be."

After learning to play golf at age 4, Palmer never stopped. It was not only Palmer's knack for golf that won him legions of adoring fans.

Long before the age of social media, Palmer was the first golfer to attract his own special following -- "Arnie's Army" -- diehard fans who surrounded every green to cheer him on, win or lose.

"When I was a boy learning to play golf in my hometown of Latrobe, Pennsylvania, I never could have imagined that one day I'd have an 'Army' of fans or that people would call me 'The King' of the sport I love," Palmer previously wrote on his website.