Hogan, whose real name was Terry Bollea, was a leading figure in wrestling during the 1980s and won six World Wrestling Entertainment championships.
He faced names including Andre the Giant and Randy Savage and enjoyed a career in the media, featuring in films and television shows.
Clearwater police department in Florida said officers and fire crews responded to a "medical-related call" on Thursday morning.
The nature of the call was a cardiac arrest, according to a police Facebook post.
The WWE star was found "experiencing a serious medical-related issue" in a house on Eldorado Avenue, Florida, and he was taken to Morton Plant Hospital.
Hogan died in hospital and there are "no signs of foul play or suspicious activity", Major Nate Burnside said.
His death was confirmed by the WWE, who posted a statement on X.
"WWE is saddened to learn WWE Hall of Famer Hulk Hogan has passed away," the statement said.
"One of pop culture's most recognisable figures, Hogan helped WWE achieve global recognition in the 1980s.
"WWE extends its condolences to Hogan's family, friends, and fans."
Hogan campaigned for US President Donald Trump's re-election to the White House.
"Hogan was MAGA all the way - Strong, tough, smart, but with the biggest heart," Trump said on Truth Social.
Hogan headlined the first Wrestlemania in 1985 and faced The Rock, aka Dwayne Johnson, during the event in 2002.
His last WWE match was against Randy Orton at SummerSlam in 2006.
Hogan's friend and fellow former professional wrestler, Ric Flair, wrote on X: "I am absolutely shocked to hear about the passing of my close friend @HulkHogan! Hulk has been by my side since we started in the wrestling business.
"An incredible athlete, talent, friend, and father!"
Hulkamania was coined in the mid-1980s, as he pushed professional wrestling into the mainstream.
He was known for his large muscles, with arms he called his 24-inch pythons, along with his bright blond hair and handlebar moustache.
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