His film roles have included those of Wally Shawn in My Dinner with Andre, Vizzini in The Princess Bride, Mr. Hall in Clueless and Rex in the Toy Story franchise. He has also appeared in a variety of television series, including recurring roles as Cyrus Rose in Gossip Girl and as Grand Nagus Zek in Star Trek: Deep Space Nine.
His plays include The Designated Mourner, Aunt Dan and Lemon and Grasses of a Thousand Colors. He also co-wrote the screenplay for My Dinner with Andre and he scripted A Master Builder, a film adaptation of of the play by Henrik Ibsen, which he also starred in. His book Essays was published in 2009 by Haymarket Books.