One of Jein's first jobs was building models for the sex comedy spoof Flesh Gordon; this was followed by work on a number of television series, commercials and movies including Wonder Woman and The UFO Incident.[8] In 1975 he was contacted by Douglas Trumbull's office and asked to do some work on Steven Spielberg's Close Encounters of the Third Kind.[8] For that film Jein contributed a number of models including miniature landscapes for UFOs to fly over, but most significantly he and his crew built the detailed mothership model that features heavily in the final sequence of the film after Spielberg decided he wanted "a more flamboyant design".[8] For their work Jein, Trumbull, Roy Arbogast, Matthew Yuricich, and Richard Yuricich were nominated for an Academy Award for Best Visual Effects at the 50th Academy Awards, but lost to the team who produced the effects for Star Wars.[8] Jein then went on to work on Spielberg's next film, 1941, where he and his team constructed a number of models including a twelve-foot model of the Ferris wheel that's dislodged from its mount and rolls down the pier and into the water.[8] For their work on 1941 Jein, William A. Fraker and A. D. Flowers were nominated for an Academy Award for Best Visual Effects at the 52nd Academy Awards but lost this time to the team who provided the effects for Ridley Scott's Alien.[9]
^Mandell, Paul (February 1979). "The Magical Techniques of Movie & TV". Starlog Magazine. No. 19. Norman Jacobs/Kerry O'Quinn. p. 63. Retrieved September 30, 2016.
^"Greg Jein obituary". Los Angeles Times. Jul 10, 2022. The LA native spent most of his life in the Crenshaw district, maintaining lifelong friendships with fellow students from Audubon Junior High and Dorsey High School. He was an Alumni of Cal State Los Angeles.
Sci-Fi and Fantasy Models magazine (UK) ran a two-part article called "So, you want to build effects miniatures?!" in issues 29 (pages 51–55) and 30 (pages 36–42), both dating from 1998. The article was by David Merriman; who was working as a subcontractor for Greg Jein. The first part includes pictures and text regarding work on a large Star Trek: The Next Generation filming model of the Enterprise-D. The second part includes pictures and text about a smaller model of the same craft; plus work on a model of the Enterprise-C and a Klingon spacecraft. Merriman also discusses unique models he built for use on episodes of Doctor Madblood.
Fantastic Films magazine, volume 1 number 4, dated October 1978, included a cover article (9 pages) by James Delson, entitled "An interview with Greg Jein: maker of the mothership from Close Encounters and other interstellar craft from Flesh Gordon, Dark Star, Laserblast, The UFO Incident and more...".