HOMICIDE: LIFE ON THE STREETS (1994) - 1 episode as Robert Ellison

THE LARRY SANDERS SHOW - 2 episodes in 1992 and 1994

FRIENDS - 1 episode in 1997

GREAT MINDS THINK FOR THEMSELVES - 12 episodes in 1997

LAW & ORDER: SVU - 1 episode in 2008 

WILFRED - 1 episode in 2012

LOUIE - 1 episode in 2012

THE CRAZY ONES - 22 episodes in 2013 and 2014

First movie was in 1977 comedy CAN I DO IT 'TILL I NEED GLASSES.  Williams had a bit part as a lawyer with a toothache.

POPEYE 1980 as Popeye

WORLD ACCORDING TO GARP (1982) as Garp

THE SURVIVORS (1983) as Donald Quinelle

MOSCOW ON THE HUDSON (1984) as Vladimir Ivanoff

THE BEST OF TIMES (1986) as Jack Dundee

CLUB PARADISE (1986) as Jack Moniker

SEIZE THE DAY (1986) as Tommy Wilhelm

GOOD MORNING, VIETNAM (1987) as Adrian Cronauer

THE ADVENTURES OF BARON MUNCHAUSEN (1988) as King of the Moon

DEAD POET'S SOCIETY (1989) as John Keating

CADILLAC MAN (1990) as Joey O'Brien

AWAKENINGS (1990) as Dr Malcolm Sayer

DEAD AGAIN (1991) as Doctor Cozy Carlisle

THE FISHER KING (1991) as Parry

HOOK (1991) as Peter Bannng

ALADDIN (1992)  as the voice of the Genie

TOYS (1992) as Leslie Zevo

MRS DOUBTFIRE (1993) as Daniel Hillard and Mrs Doubtfire

BEING HUMAN (1994) as Hector

NINE MONTHS (1995) as Dr Kosevich

JUMANJI (1995) as Alan Parish

THE BIRDCAGE (1996) as Armand Goldman 

JACK (1996) as Jack Powell

FATHERS' DAY (1997) as Dale Putley

FLUBBER (1997) as Professor Philip Brainard

GOOD WILL HUNTING (1997) as Sean Maguire. Williams won best supporting actor at the Academy Awards for this role.

PATCH ADAMS (1998) as Patch Adams

BICENTENNIAL MAN (1999) as Andrew Martin

AI ARTIFICIAL INTELLIGENCE (2001) as Dr Know

ONE HOUR PHOTO (2002) as Seymour Parrish

INSOMNIA (2002) as Walter Finch

THE FINAL CUT (2004) as Alan Hakman

ROBOTS (2005) as Fender

RV (2006) as Bob Munro

MAN OF THE YEAR (2006) as Tom Dobbs

HAPPY FEET (2006) as Ramon and Lovelace

NIGHT AT THE MUSEUM (2006) as Teddy Roosevelt

NIGHT AT THE MUSEUM: BATTLE OF THE SMITHSONIAN (2009) as Teddy Roosevelt

OLD DOGS (2009) as Dan

HAPPY FEET TWO (2011) as Ramon and Lovelace

MERRY FRIGGIN' CHRISTMAS (2014) as Mitch (lead role)

NIGHT AT THE MUSEUM: SECRET OF THE TOMB (2014) as Teddy Roosevelt, alongside Rebel Wilson and Ben Stiller.

ABSOLUTELY ANYTHING (2015) as the voice of Dennis the Dog, alongside Simon Pegg and John Cleese