Berg became fascinated by special effects in movies since he saw Ernest B. Schoedsack's Mighty Joe Young (1949), featuring master technician Ray Harryhausen's effects.
Berg began working for Cascade Pictures producing TV commercials. This company also hired Dennis Muren and Phil Tippett, both of whom would eventually work for Industrial Light & Magic.
Working as production assistant, Berg went to the set of Jack Hill and Juan Ibáñez's House of Evil (1968), a Mexican-American production, where he had a chance to meet horror star and his personal idol Boris Karloff. Berg retains a fond memory of this meeting.
Berg's first confirmed job was uncredited: He worked on sci-fi B-movie The Further Adventures of Major Mars (1976), and then as miniature builder for The Crater Lake Monster (1977), although this time he was credited, alongside colleague Tippett.
Berg worked as a stop-motion animator, as Harryhausen did before him, for Star Wars: Episode IV A New Hope (1977). He moved different creatures, especially in the famous cantina scene, and he was also supposed to act as different aliens. Although uncredited, he is known to have played Momaw Nadon, the "Hammerhead"; and also one of the arguing Duros. He may have played one of the cantina band members, particularly Tech Mo'r, the ommni box player; however, this role is unconfirmed and even today a polemic question among experts.
Berg continued with science-fiction and horror films in the late 1970s, being credited as the only visual-effects artist (model sculptor) for Michael Rae's Laserblast (1978) and as the only special-effects artist in Joe Dante's Piranha (1978). In the latter movie, he worked with special-effects legend Chris Walas.
He returned to the Star Wars saga for Star Wars: Episode V The Empire Strikes Back (1980), again as a stop-motion animator, although he was not officially billed for that part.
After that, he worked again with Chris Walas for Matthew Robbins' Dragonslayer; Berg is credited as a "dragon consultant."
Berg returned to George Lucas' crew for Star Wars: Episode VI Return of the Jedi (1983) as a creature consultant. The following year, John Korty's TV movie The Ewok Adventure (1984) featured special effects by Berg and Star Wars colleagues Dennis Muren, Phil Tippett and Michael Pangrazio. All of them got an Emmy Award for Outstanding Special Visual Effects, although shared with other TV movies and series. The book Industrial Light & Magic: The Art of Special Effects (1986, Thomas G. Smith) says that Berg also portrayed the Gorax in the movie.
In 1984, Berg also worked as a consultant or advisor on other movies, including Joe Dante's Gremlins (again with Walas); Peter Hyams' 2010, for Entertainment Effects Group; and Ivan Reitman's Ghostbusters, again for Entertainment Effects Group.
However, Berg left Entertainment Effects Group for CWI: Chris Walas Inc. Alongside other special-effects artists from Star Wars, such as Don Bies and Howie Weed, he worked in David Cronenberg's The Fly (1986), being nominated for a BAFTA Award for the Best Special Effects. The nominees for The Fly included Berg and Walas, as well as Louis Craig and Hoyt Yeatman. The award was ultimately given to the film The Witches of Eastwick (1987).
Berg returned to CWI for Walas' debut as a director in The Fly II (1989), where Berg was the creature effects supervisor.
During the early 1990s, Berg created monsters. He made robots for Irvin Kershner's Robocop 2 (1990) (with Howie Weed working for him), and then was a technical advisor for David Cronenberg's fantasy Naked Lunch (1991). He then made molds for Tim Burton's The Nightmare Before Christmas (1993).
His experience with Burton would be useful more than ten years after that, when he joined the Star Wars saga for a fifth time, working as model maker in the sixth installment of the saga, Star Wars: Episode III Revenge of the Sith (2005). In the meantime, Jon Berg has also been responsible for creating the statue used for the , and he was also credited as guest animator in the short Robot Chicken: Star Wars Episode II.
Berg is currently active as a special-effects artist.
- Star Wars Insider 49 Interview: "Jon Berg: The Stop-Motion Animation of Episode V," pages 68–69
- "Creature Creator" — Star Wars Insider 147