Filmography
| Year | Title | Role |
| 2015 | Absolutely Anything | Dennis |
| 2014 | Night at the Museum: Secret of the Tomb | Teddy Roosevelt |
| 2014 | The Angriest Man in Brooklyn | Henry Altmann |
| 2014 | Altman | Self |
| 2014 | A Merry Friggin' Christmas | Mitch |
| 2014 | Boulevard | Nolan Mack |
| 2013 | The Big Wedding | Rev. Moinighan |
| 2013 | Lee Daniels' The Butler | Dwight Eisenhower |
| 2013 | The Face of Love | Roger |
| 2011 | Happy Feet Two in 3D | Ramon/Lovelace |
| 2009 | Night at the Museum: Battle of the Smithsonian | Teddy Roosevelt |
| 2009 | Old Dogs | Dan |
| 2009 | World's Greatest Dad (2009) | Lance Clayton |
| 2009 | Shrink | Holden |
| 2007 | License to Wed | Reverend Frank |
| 2007 | August Rush | Wizard |
| 2007 | Certifiably Jonathan | Self |
| 2006 | Man of the Year | Tom Dobbs |
| 2006 | Happy Feet | Ramon/Lovelace |
| 2006 | RV (2006) | Bob Munro |
| 2006 | The Night Listener | Gabriel Noone |
| 2006 | Night at the Museum | Theodore Roosevelt |
| 2006 | Everyone's Hero | Napoleon Cross |
| 2005 | The Big White | Paul Barnell |
| 2005 | Robots: The IMAX Experience | Fender |
| 2004 | House of D | Pappass |
| 2004 | The Final Cut (2004) | Alan Hakman |
| 2004 | Noel | Charlie |
| 2002 | One Hour Photo | Seymour "Sy" Parrish |
| 2002 | Death to Smoochy | Randolph |
| 1999 | Bicentennial Man | Andrew Martin |
| 1999 | Jakob the Liar | Jakob Heym/Narrator |
| 1999 | Get Bruce! | Self |
| 1998 | What Dreams May Come | Chris Nielsen |
| 1998 | Patch Adams | Hunter "Patch" Adams |
| 1997 | Deconstructing Harry | Mel / Harry's Character |
| 1997 | Flubber | Professor Philip Brainard |
| 1997 | Good Will Hunting | Sean Maguire |
| 1997 | Fathers' Day | Dale Putley |
| 1996 | The Birdcage | Armand Goldman |
| 1996 | The Secret Agent | The Assassin |
| 1996 | Hamlet – NT Live 10th Anniversary | Osric |
| 1995 | Nine Months | Dr. Kosevich |
| 1994 | Being Human | Hector |
| 1993 | Mrs. Doubtfire | Daniel Hillard/Mrs. Euphegenia Doubtfire |
| 1992 | FernGully ... the Last Rainforest | Batty Koda |
| 1992 | Aladdin (1992) | Genie |
| 1992 | Toys (1992) | Leslie Zevo |
| 1991 | The Fisher King | Henry Sagan, 'Parry' |
| 1991 | Hook | Peter Banning/Peter Pan |
| 1991 | Shakes the Clown | Mime Jerry (as Marty Fromage) |
| 1991 | Dead Again | Dr. Cozy Carlisle |
| 1990 | Awakenings | Dr. Malcolm Sayer |
| 1989 | The Adventures of Baron Munchausen | King of the Moon |
| 1989 | Dead Poets Society | John Keating |
| 1987 | Good Morning, Vietnam | A2C Adrian Cronauer |
| 1986 | Seize the Day | Tommy Wilhelm |
| 1986 | The Best of Times | Jack Dundee |
| 1984 | Moscow on the Hudson | Vladimir Ivanoff |
| 1982 | The World According to Garp | Garp |
| 1982 | An Evening With Robert Williams | Actor |
| 1980 | Popeye (1980) | Popeye |
| 1979 | Can I Do It 'til I Need Glasses | Actor |
