Robin Williams, who died Monday at age 63, harnessed his zany comic persona to become one of Hollywood’s most celebrated and bankable movie stars.

Mr. Williams was found dead at his home in Tiburon, Calif., just north of San Francisco, according to the Marin County Sheriff’s Office.

The apparent cause of death was suicide by asphyxiation, although an investigation is continuing.

Emergency personnel found Mr. Williams inside the house he shared with his wife, Susan Schneider, after a 911 call reported a man unconscious and not breathing. The sheriff’s office said Mr. Williams was last seen alive at 10 p.m. on Sunday.

Mr. Williams’s high energy at times masked a personal struggle with alcohol and drug addiction, and a representative for the actor said Monday that “he has been battling severe depression of late.”

After starting his career in stand-up comedy and bursting into public consciousness in 1978 with the hit television comedy “Mork & Mindy,” Mr. Williams built an acting career that included a mix of over-the-top star vehicles like “Mrs. Doubtfire” and “The Birdcage,” along with well-received roles in dramas including “Awakenings” and “Insomnia.”

He was nominated for four Oscars, winning best supporting actor for his role as a therapist to a troubled young math genius in “Good Will Hunting,” which was released in 1997. “This might be the one time I’m speechless,” he said upon accepting the award.

Since his days on “Mork & Mindy,” a fish-out-of-water tale that ran for four seasons in which he played an alien from the planet Ork, Mr. Williams demonstrated a fully formed comedic style filled with tics and habits that would become his trademarks. – Wall Street Journal