Los Angeles police say officers responded to Rooney's North Hollywood home at 4:35 p.m. and attempted to perform CPR to no avail. They say it appears Rooney died of natural causes. He was with his family at the time of his death.
With two Oscars and 200 films to his credit, Rooney was a Hollywood institution. Acting was quite literally in his blood. The actor started his career in his parents' vaudeville act while still a toddler, and broke into movies before age 10.
But it was as the all-American teenager, Andy Hardy, that Rooney got his big break. MGM turned the Hardy family adventures into a series of 15 films. Young Andy found love with Judy Garland and young Mickey found stardom.
In 1939, he was the biggest box office draw in the country with a string of hits, including "Boys Town" and "Babes in Arms."
In 1944, he starred with Elizabeth Taylor in "National Velvet." It was Hollywood's "Golden Age" and the best of times for Rooney. But he was drafted during WWII. When he returned all grown up, his career took a downturn. His movies flopped, and so did seven marriages, including one to movie star Ava Gardner.
Rooney finally found happiness with his eighth wife, Jan Chamberlin, and he found success on screen again in films like "The Black Stallion."
In 1983, the Academy gave Rooney an honorary Oscar for lifetime achievement. Despite the recognition, Rooney felt cheated by Hollywood, bitter that he was never able to capitalize on his early success.
"We didn't make big money in those days. I never made big money in my life," said Rooney.
So out of necessity - and love - Rooney acted until the end. When once asked what he wanted as his epitaph, Rooney said, "I said just two words: 'I tried.'"
Among his roles in recent years was a part as a guard in the smash 2006 comedy "A Night at the Museum."
The Associated Press contributed to this report.