"American Icon and Playboy Founder, Hugh M. Hefner passed away today. He was 91," Playboy said in a tweet.
"My father lived an exceptional and impactful life as a media and cultural pioneer and a leading voice behind some of the most significant social and cultural movements of our time in advocating free speech, civil rights and sexual freedom," said Cooper Hefner, chief creative officer of Playboy Enterprises.
"He defined a lifestyle and ethos that lie at the heart of the Playboy brand, one of the most recognizable and enduring in history. He will be greatly missed by many, including his wife Crystal, my sister Christie and my brothers David and Marston and all of us at Playboy Enterprises."
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Hefner launched Playboy in his native Chicago in 1953, placing Marilyn Monroe on the first cover.
The circulation grew to 200,000 within a year and hit 1 million in 5 years.
He built the company into one of the most recognizable global brands, including not only pictures of nude women in the centerfold, but also articles on literature, politics and culture.
Hugh Hefner through the years
By the 1970s, the magazine had more than 7 million readers and had inspired such raunchier imitations as Penthouse and Hustler.
Hefner later relocated to Los Angeles, establishing the Playboy Mansion West in Holmby Hills in the 1970s. The company expanded into other ventures, including hotels, modeling agencies and television.
In the 1980s, he turned over leadership of the company to his daughter Christie, naming her as chair and chief executive officer.
Competition and the internet reduced circulation to less than 3 million by the 21st century, and the number of issues published annually was cut from 12 to 11.
The magazine made perhaps its most radical change in 2016 when it decided to stop using photos of fully unclothed women in an attempt to broaden its newsstand appeal. That experiment only lasted a year and the magazine brought back nudity in spring 2017.
Tributes were pouring in from celebrities who had appeared in the magazine or knew Hefner.
One of the more famous playmates was Jenny McCarthy, Playmate of the Year for 1994, who tweeted: "RIP #Hef. Thank you for being a revolutionary and changing so many people's lives, especially mine. I hope I made you proud."
Rocker Gene Simmons - whose wife Shannon Tweed was Playmate of the Year in 1982 and at one point lived at the Playboy Mansion - tweeted: "A great man, entrepreneur and innovator. Your legacy lives on. #Hef."
Fans of Hefner headed out to the Playboy Mansion to pay tribute to him not long after the news of his death broke out.
Some of the most legendary parties happened at the Mansion, and many of them were for charitable causes.
"Not only humanitarian, but he was really in the forefront for women's rights. A lot of people see the opposite, but (he was for) women's rights, gay rights and race rights. So he was really a legend and a hero," said Richard Gitterman, owner of a tour company.
Some people dropped off flowers and said his legacy will live on.
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The Associated Press contributed to this report.