John Dezso Ratzenberger is an American actor, voice actor, and entrepreneur. He played Cliff Clavin in the TV show Cheers, for which he earned two Emmy nominations, and plays voice roles in Pixar Animation Studios' films, including Hamm in the Toy Story franchise, The Underminer in The Incredibles franchise, and Mack in the Cars franchise. He is the only actor to appear in all of Pixar's feature films, and with minor appearances in major films such as Superman and The Empire Strikes Back, he is one of the most successful actors of all time in terms of box-office receipts.Born in Bridgeport, Connecticut, Ratzenberger began his entertainment career while living in London in the 1970s. He had minor film and television roles throughout the late 70s and early 1980s before creating, and then landing, the role of the know-it-all mailman Cliff Clavin on Cheers, a role he portrayed throughout the show's eleven seasons.