He may have been best known for his fast-talking, funnyman roles, but he mesmerised in serious ones as well and was memorable well beyond the big screen: on television, on the comedy stage, even on Broadway.
Here are 10 of his most distinctive roles:
Good Will Hunting (1997) - A rare but welcome serious role for Williams, who played the stubborn yet empathetic therapist who was somehow able to help maths prodigy Will Hunting (Matt Damon) figure out how to handle his life. Won a supporting actor Oscar.
Mrs Doubtfire (1991) - Who couldn't love a bumbling father who dressed up as a portly nanny - with a latex mask, a wig and a Scottish accent - in order to spend time with his young children? (A sequel was in the works.)
Aladdin (1992) - Will it ever be possible to see a cartoon genie and not think of Williams? Remember him shooting out of that bottle: "Ten thousand years will give you SUCH a crick in the neck!"
Good Morning, Vietnam (1987) - Williams' fast-talking style was perfect for the role of a DJ on Armed Forces Radio during the Vietnam War. (First Oscar nomination.)
One Hour Photo (2002) - Another serious role, and it was a creepy one. Williams played a photo counter worker at a huge suburban store who got a little too involved in the lives of his customers when he realised one of them was having an affair.
Dead Poets Society (1989) - Played an unconventional poetry teacher who taught his Vermont boarding school students to stand on their desks, think on their own, and "seize the day". (Second Oscar nomination.)
The Fisher King (1991) - Williams played a half-mad homeless man, convinced that the Holy Grail was sitting in the Fifth Avenue abode of a billionaire. (Third Oscar nomination).
Mork & Mindy (1978-1982) - Mork from Ork. Nanu, nanu. What more needs to be said? This TV series, a spin-off from Happy Days, is how many of us first learned of Williams' sublime nuttiness.
Moscow On The Hudson (1984) - Williams played a Russian - quite credibly - in this film about a comically lovable circus saxophonist, Vladimir, who defects while touring New York (turning himself in at Bloomingdale's, naturally).
Bengal Tiger At The Baghdad Zoo (2011) - Appearing on Broadway, Williams gave an admirably thoughtful performance in the role of a tiger - actually, the ghost of a dead tiger - locked up at the Baghdad Zoo at the time of the US invasion in 2003.