The actor's son, Michael Douglas, announced his death on behalf of the Douglas family Wednesday in an Instagram post.
"To the world, he was a legend, an actor from the golden age of movies who lived well into his golden years, a humanitarian whose commitment to justice and the causes he believed in set a standard for all of us to aspire to," he wrote.
Kirk Douglas, who bravely and publicly fought his way back from a severe stroke in 1996, will be remembered for the grit and determination he showed on screen in action epics like "Spartacus"and "20,000 Leagues Under the Sea," as well as more intimate character studies like "Lonely Are the Brave." But it was his commitment to higher ideals in the film industry proved even more dramatic.
The actor was responsible for helping to break Hollywood's infamous blacklist at the height of Cold War paranoia when he was instrumental in hiring and crediting legendary screenwriter Dalton Trumbo, a member of the so-called "Hollywood Ten," for his work on "Spartacus." Douglas was also a committed philanthropist and the father of an iconic actor in his own right, Michael Douglas.
"I've known Kirk Douglas personally and appreciate his friendship," President Jimmy Carter said while awarding Douglas the Presidential Medal of Freedom, the nation's highest civilian honor, in 1981. "But more than that, I have known how dedicated he is to using his talent as an actor and a director and the esteem with which he's held by his own people in spreading the good news about this country and explaining our purposes, our ideals, our commitments, and our achievements, our hopes, and our dreams to people around the world."
The progressive values of Douglas may been the product of his upbringing, as the poor child of Jewish immigrants from what's now Belarus — his birth name was Issur Danielovitch — who grew up in Amsterdam, New York.
After cutting his teeth as a stage actor and scoring strong supporting roles in classic films like "Out of the Past," Douglas would eventually emerge as a star in his own right with the 1949 boxing drama "Champion," for which he earned the first of three Best Actor Academy Award nominations. (He would eventually take home a Lifetime Achievement Oscar in 1996).
That film, and in his subsequent hits that followed, Douglas broke with the tradition of unflappable leading men by portraying complex and often morally-conflicted characters that tested audiences sympathies.
Meanwhile, in tough, trenchant films like "Ace In the Hole," "Paths of Glory," and "Seven Days in May," Douglas also didn't shy away from challenging subject matter such as corruption of the press and the military.
Douglas pursued his passions without sacrificing his popular appeal: he ranked among the top 25 box office stars by the Quigley Publishing Company for six straight years from 1957 to 1963. And even as his production began to tail off in later decades, the cleft-chinned star remained a virile sex symbol well into his sixties.
The pace Douglas kept as a perpetual A-lister did take a toll on his relationship with his family. He split from Michael's mother when his famous son was only 6 years old.
"[Kirk] was a rager early on. He was overworked. He was doing five-plus pictures a year," Michael Douglas told Men's Journal in 2013. "I just sort of stayed out of his way, but he did the best he could'.
Over the years, the two famous men would repair their relationship and even appear alongside each other (along with Kirk's embattled grandson Cameron) in the 2003 drama "It Runs In the Family." And he stood by his son Michael's side when he battled stage IV cancer in 2010.
He also began blogging in his nineties, attracting a new generation of fans, and his twelfth book, co-written with his wife of 62 years, Anne Buydens Douglas, called "Kirk and Anne: Letters of Love, Laughter, and a Lifetime in Hollywood," was published in 2017.
Douglas received a standing ovation at the 2018 Golden Globe awards, sharing the spotlight with his daughter in law, Catherine Zeta-Jones, who presented an award.
The honorary Oscar recipient is survived by his wife, and three sons, Michael, Peter, and Joel Douglas. His youngest son with Buydens, Eric, died in 2004 of what was ruled an accidental drug overdose.