| An | Titlu | Rol | Note |
|---|
| 1974 | The Country Girl | Paul Unger | Film TV |
| 1977 | Great Performances | Capt. Thorne | Episodul: "Secret Service" |
| 1980 | The Oldest Living Graduate | Clarence | Film TV |
| 1980 | Mom, the Wolfman and Me | Wally | Film TV |
| 1980 | Big Blonde | Herbie Morse | Film TV |
| 1982 | Not in Front of the Children | Richard Carruthers | Film TV |
| 1983 | Ziua de după (The Day After) | Joe Huxley | Film TV |
| 1984 | Faerie Tale Theatre | Goldilocks' father | Episodul: "Goldilocks and the Three Bears" |
| 1984 | Cupola strălucitoare (The Glitter Dome) | Marty Wellborn | Film TV |
| 1985–1988 | Saturday Night Live | Rolul său (gazdă) | 3 episoade |
| 1986 | Amazing Stories | John Walters | Episodul: "The Doll" |
| 1986 | Resting Place | Kendall Laird | Film TV |
| 1987 | Baby Girl Scott | Neil Scott | Film TV |
| 1989 | Traveling Man | Ben Cluett | Film TV |
| 1990 | Ivory Hunters | Robert Carter | Film TV |
| 1991 | The Boys | Artie Marguiles | Film TV |
| 1994 | World War II: When Lions Roared | Franklin Delano Roosevelt | Film TV |
| 1995 | Tales from the Crypt | Dr. Oscar Charles | Episodul: "You, Murderer" |
| 1995 | Frasier | Madman Martinez | Episodul: "Someone to Watch Over Me" |
| 1995 | Redwood Curtain | Laird | Film TV |
| 1995 | My Brother's Keeper | Tom Bradley / Bob Bradley | Film TV |
| 1995 | The Tuskegee Airmen | Senator Conyers | Film TV |
| 1996–2001 | 3rd Rock from the Sun | Dr. Dick Solomon | 139 episoade |
| 1999 | Cosby | Rolul său | Episodul: "Superstar" |
| 2000 | Don Quixote | Don Quixote de la Mancha/Alonso Quijano | Television film Also executive producer |
| 2003 | Freedom: A History of Us | Various roles | 4 episoade |
| 2004 | My Life, Inc. | Jan van de Bunt | Voce Pilot |
| 2005 | Nova | Narrtor | Voice Episodul: " E=mc²: Einstein's Big Idea" |
| 2006–2008 | Twenty Good Years | John Mason | 13 episoade |
| 2009 | Dexter | Arthur Mitchell | 12 episoade |
| 2009 | The National Parks: America's Best Idea | Himself | 2 episoade |
| 2009 | 30 Rock | Rolul său | Episodul: "Goodbye, My Friend" |
| 2011–2014 | How I Met Your Mother | Jerry Whitaker | 4 episoade |
| 2011 | Prohibition | HL Mencken | 3 episoade |
| 2013 | Timms Valley | Ol' Gregory Timms | Voce Pilot |
| 2013–2014 | Once Upon a Time in Wonderland | Percy the White Rabbit | Voce 9 episoade |
| 2014 | Drunk History | William Randolph Hearst and George Washington (Benedict Arnold) | Episodul: "Hollywood" and "Philadelphia" |
| 2015 | Louie | Funny Man | Episodul: "Sleepover" |