He is, however, probably most famous for his Emmy-nominated role as Cliff Clavin on the TV show Cheers. Besides voicing a character in all Pixar films, he is also a team member of the Pixar Softball Team. Ratzenberger also hosted the documentary film Pixar: 20 Years of Animation and Counting. He said in an interview that out of all the characters he has voiced for Pixar, P.T. Flea from A Bug's Life is his favorite one that he's done. Ratzenberger was married to Georgia Stiny from 1984-2004 (divorced) by whom he has two children: a son named James John Ratzenberger born in 1987 and a daughter named Nina Katherine Ratzenberger born in 1989.
On November 6, 2012, John Ratzenberger married his girlfriend Julie Blichfeldt.
- Yeti in Monsters University has the shortest dialogue in all the Pixar films so far, as he only has one line which is shorter than his line as the Underminer in The Incredibles.
- Gordon in Brave has a few quotes at the beginning of the film. Seemingly, Ratzenberger, along with Steve Purcell, is one of the few American voice actors in the film, as everyone else is from the United Kingdom and Ireland.
- P.T. Flea in A Bug's Life is his favorite role that he has done for Pixar.
- Ratzenberger had a cameo in DisneyToon Studios' Cars spin-off Planes, as the voice of jet tug Harland. He also voiced Brodi Enid in the film's sequel Planes: Fire & Rescue.
- John in WALL•E may be a caricature of Ratzenberger himself, since he shares his first name.