Williams was found dead in his home in Paradise Cay, California, on August 11, 2014. The final autopsy report, released in November 2014, concluded that Williams's death was a suicide resulting from "asphyxia due to hanging".

However, Lewy bodies can also cause Lewy body dementia. An autopsy three months after Williams' death showed he had this, rather than Parkinson's disease. "Clinically he had PD, but pathologically he had diffuse LBD. The predominant symptoms Robin had were not physical—the pathology more than backed that up.

The movie "Boulevard" shot before Robin Williams died nearly a year ago. It is his last film to hit the big screen. Williams plays a middle-class man in his sixties with a stable marriage and desk job. "Every once in a while I'd say to Robin, 'Hey, this is a big deal.

His mother, Laura, was a former model from New Orleans, Louisiana. His father, Robert Fitzgerald Williams was a senior executive at Ford Motorship in charge of the Midwest area. He is of English, Welsh and Irish descent on his father's side, and of French descent on his mother's side.