San Francisco ? Robin Williams, the Academy Award winner and comic supernova whose explosions of pop culture riffs and impressions dazzled audiences for decades and made him a gleamy-eyed laureate for the Information Age, died Monday in an apparent suicide. He was 63.

Williams was pronounced dead at his home in California on Monday, according to the sheriff’s office in Marin County, north of San Francisco. The sheriff’s office said a preliminary investigation shows the cause of death to be a suicide due to asphyxia.

“This morning, I lost my husband and my best friend, while the world lost one of its most beloved artists and beautiful human beings. I am utterly heartbroken,” said Williams’ wife, Susan Schneider. “On behalf of Robin’s family, we are asking for privacy during our time of profound grief. As he is remembered, it is our hope the focus will not be on Robin’s death, but on the countless moments of joy and laughter he gave to millions,”

Williams had been battling severe depression recently, said Mara Buxbaum, his press representative.

From his breakthrough in the late 1970s as the alien in the hit TV show “Mork and Mindy,” through his standup act and such films as “Good Morning, Vietnam,” the short, barrel-chested Williams ranted and shouted as if just sprung from solitary confinement. Loud, fast, manic, he parodied everyone from John Wayne to Keith Richards, impersonating a Russian immigrant as easily as a pack of Nazi attack dogs.

He was a riot in drag in “Mrs. Doubtfire,” or as a cartoon genie in “Aladdin.” He won his Academy Award in a rare, but equally intense dramatic role, as a teacher in the 1997 film “Good Will Hunting.”

Like so many funnymen, he had serious ambitions, winning his Oscar for his portrayal of an empathetic therapist in “Good Will Hunting.” He also played for tears in “Awakenings,” ”Dead Poets Society” and “What Dreams May Come,” something that led New York Times critic Stephen Holden to once say he dreaded seeing the actor’s “Humpty Dumpty grin and crinkly moist eyes.”

Williams also won three Golden Globes, for “Good Morning, Vietnam,” ”Mrs. Doubtfire” and “The Fisher King.”

His other film credits included Robert Altman’s “Popeye” (a box office bomb), Paul Mazursky’s “Moscow on the Hudson,” Steven Spielberg’s “Hook” and Woody Allen’s “Deconstructing Harry.” On stage, Williams joined fellow comedian Steve Martin in a 1988 Broadway revival of “Waiting for Godot.”

His personal life was often short on laughter. He had acknowledged drug and alcohol problems in the 1970s and ’80s and was among the last to see John Belushi before the “Saturday Night Live” star died of a drug overdose in 1982.

Born in Chicago in 1951, Williams would remember himself as a shy kid who got some early laughs from his mother — by mimicking his grandmother. He opened up more in high school when he joined the drama club and he was accepted into the Juilliard Academy, where he had several classes in which he and Christopher Reeve were the only students and John Houseman was the teacher.

Encouraged by Houseman to pursue comedy, Williams identified with the wildest and angriest of performers: Jonathan Winters, Lenny Bruce, Richard Pryor, George Carlin. Their acts were not warm and lovable. They were just being themselves.

He unveiled Mork, the alien from the planet Ork, in an appearance on “Happy Days,” and was granted his own series, which ran from 1978-1982.

In subsequent years, Williams often returned to television — for appearances on “Saturday Night Live,” for “Friends,” for comedy specials, for “American Idol,” where in 2008 he pretended to be a “Russian idol” who belts out a tuneless, indecipherable “My Way.”

Winner of a Grammy in 2003 for best spoken comedy album, “Robin Williams — Live 2002,” he once likened his act to the daily jogs he took across the Golden Gate Bridge. There were times he would look over the edge, one side of him pulling back in fear, the other insisting he could fly.

“You have an internal critic, an internal drive that says, ‘OK, you can do more.’ Maybe that’s what keeps you going,” Williams said. “Maybe that’s a demon. … Some people say, ‘It’s a muse.’ No, it’s not a muse! It’s a demon!”