Rooney died Sunday at age 93 surrounded by family at his North Hollywood home, police said. The Los Angeles County Coroner's office said Rooney died a natural death.
There were no further details immediately available on the cause of death, but Rooney did attend Vanity Fair's Oscar party last month, where he posed for photos with other veteran stars and seemed fine. He was also shooting a movie at the time of his death, "The Strange Case of Dr. Jekyll and Mr. Hyde," with Margaret O'Brien.
He was nominated for four Academy Awards over a four-decade span and received two special Oscars for film achievements, won an Emmy for his TV movie "Bill" and had a Tony nomination for his Broadway smash "Sugar Babies."
"I loved working with Mickey on 'Sugar Babies.' He was very professional, his stories were priceless and I love them all ... each and every one. We laughed all the time," Carol Channing said.
A small man physically, Rooney was prodigious in talent, scope, ambition and appetite. He sang and danced, played roles both serious and silly, wrote memoirs, a novel, movie scripts and plays and married eight times, siring 11 children.
His first marriage — to the glamorous, and taller, Ava Gardner — lasted only a year. But a fond recollection from Rooney years later — "I'm 5 feet 3, but I was 6 feet 4 when I married Ava" — summed up the man's passion and capacity for life.
Rooney began as a toddler in his parents' vaudeville act in the 1920s. He was barely six when he first appeared on screen, playing a midget in the 1926 silent comedy short "Not to Be Trusted," and he was still at it more than 80 years later, working incessantly as he racked up about 250 screen credits in a career unrivaled for length and variety.
"I always say, 'Don't retire — inspire,'" Rooney said in an interview with The Associated Press in March 2008. "There's a lot to be done."
This from a man who did more than just about anyone in Hollywood and outlasted pretty much everyone from old Hollywood.
Rooney was among the last survivors of the studio era, which his career predated, most notably with the lead in a series of "Mickey McGuire" kid comedy shorts from the late 1920s to early '30s that were meant to rival Hal Roach's "Our Gang" flicks.
After signing with MGM in 1934, Rooney landed his first big role playing Clark Gable's character as a boy in "Manhattan Melodrama." A year later, still only in his mid-teens, Rooney was doing Shakespeare, playing an exuberant Puck in Max Reinhardt's "A Midsummer Night's Dream," which also featured James Cagney and Olivia de Havilland.
Rooney soon was earning $300 a week with featured roles in such films as "Riff Raff," "Little Lord Fauntleroy," "Captains Courageous" and "The Devil Is a Sissy."
Then came Andy Hardy in the 1937 comedy "A Family Affair," a role he would reprise in 15 more feature films over the next two decades. Centered on a kindly small-town judge (Lionel Barrymore) who delivers character-building homilies to troublesome son Andy, it was pure corn, but it turned out to be golden corn for MGM, becoming a runaway success with audiences.
"I knew 'A Family Affair' was a B picture, but that didn't stop me from putting my all in it," Rooney recalled.
Studio boss Louis B. Mayer saw "A Family Affair" as a template for a series of movies about a model American home. Cast changes followed, most notably with Lewis Stone replacing Barrymore in the sequels, but Rooney stayed on, his role built up until he became the focus of the films, which included "The Courtship of Andy Hardy," "Andy Hardy's Double Life" and "Love Finds Andy Hardy," the latter featuring fellow child star Garland.