In the mid-1980s, Wham! was one of the most successful pop duos ever, ahead even of Simon & Garfunkel, with singles like "Wake Me Up Before You Go-Go", "Careless Whisper", "Last Christmas" and "The Edge of Heaven".
"It is with great sadness that we can confirm our beloved son, brother and friend George passed away peacefully at home over the Christmas period," his publicist said in a statement.
"The family would ask that their privacy be respected at this difficult and emotional time. There will be no further comment at this stage," the statement said.
British police said Michael's death was "unexplained but not suspicious."
Born Georgios Kyriacos Panayiotou June 25, 1963 in London to Greek Cypriot immigrant parents in a flat above a north London laundrette, Michael once played music on the London underground train system before finding fame with Wham!.
With a school friend, Andrew Ridgeley, he formed Wham! in 1981, a partnership that would produce some of the most memorable pop songs and dance-floor favorites of the 1980s.
"I am in deep shock," said Elton John. "I have lost a beloved friend - the kindest, most generous soul and a brilliant artist. My heart goes out to his family and all of his fans. @GeorgeMichael #RIP."
'I WANT YOUR SEX'
The duo had their first hit with their second release "Young Guns (Go For It)" (1982) before their debut release "Wham Rap" became a hit the following year. The 1984 album "Make It Big" was a huge success in the United States.
"No way could I have done it without Andrew," Michael once said. "I can't think of anybody who would have been so perfect in allowing something which started out as a very naive, joint ambition, to become what was still a huge double act but what was really...mine."
But Michael was keen to reach beyond Wham!'s teenage audience and to experiment with other genres. Wham! announced their split in 1986.
A pilot solo single "I Want Your Sex" was banned by daytime radio stations but was one of his biggest hits.
"I want your sex, I want you, I want your sex," he sang. "So why don't you just let me go, I'd really like to try, Oh I'd really love to know, When you tell me you're gonna regret it, Then I tell you that I love you but you still say no!"
In the space of the next five years, Michael had six U.S. Number One hit singles including "Faith", "Father Figure", "One More Try", "Praying For Time" and a duet with Aretha Franklin "I Knew You Were Waiting For Me".
Questions about his sexuality were raised when he was arrested in 1998 for "engaging in a lewd act" in a public restroom of the Will Rogers Memorial Park in Beverly Hills, California.
"I feel stupid and reckless and weak for letting my sexuality be exposed that way," Michael told CNN at the time. "But I do not feel shame [about my sexuality], neither do I think I should."
"I can try to fathom why I did what I did," he continued, "but at the end of the day, I have to admit that maybe part of the kick was that I might get found out," he told CNN.
Though he had relationships with women and once told family members that he was bisexual, Michael, then 34, said he was gay.
"Rest with the glittering stars, George Michael," said Star Trek actor and LGBT rights activist George Takei. "You've found your Freedom, your Faith. It was your Last Christmas, and we shall miss you."
While Prime Minister Margaret Thatcher was in power, Michael voted for Britain's opposition Labour Party but criticized Tony Blair's support for George W. Bush's 2003 invasion of Iraq.
"Sad to hear that George Michael has died," said current Labour Party leader Jeremy Corbyn. "He was an exceptional artist and a strong supporter of LGBT and workers' rights."
Michael's death comes at the end of a year that has seen the passing of several music superstars, including David Bowie, Prince and Leonard Cohen. Rick Parfitt, the guitarist of British rock group Status Quo, died on Saturday at 68.