- The Penguin for Batman: The Animated Series
- Little Enos Burdette in Smokey and the Badit
- Virgil in Battle for the Planet of the Apes
- Swan in Phantom of the Paradise
Did you know...
- Since 2009, Williams has been the president and chairman of the American songwriting society ASCAP.
- Made Tonight Show history by surprising Johnny Carson when he showed up in his full ape makeup and costume from Battle For The Planet Of Apes and sang Here's That Rainy Day.
- Upon winning the Academy Award for best original song (Evergreen from 1976's A Star Is Born) his acceptance speech opened with “I was going to thank all the little people, then I remembered I am the little people.”