He began working in the film industry for The Fly (1986) when he was 24 years old. After working on The Kiss (1988) and The Fly II (1989), he was hired by Industrial Light & Magic. With the company, he worked on films such as Indiana Jones and the Last Crusade (1989), Congo (1995), Starship Troopers (1997), A.I. (2001), and Pirates of the Caribbean (2003).
1997 marked the release of Bies's first collaboration with Star Wars, where he worked as creature and model maker in the special editions of both Star Wars: Episode V The Empire Strikes Back and Star Wars: Episode VI Return of the Jedi. Bies also makes a cameo as one of the aliens in Return of the Jedi, playing a Bith named Barquin D'an, the Kloo horn player from the Max Rebo Band. He also replaced Jeremy Bulloch as the charismatic Boba Fett for some new scenes. He also constructed the props used in Star Wars: Jedi Knight: Dark Forces II released the same year.
In 1999, he also began work on Star Wars: Episode I The Phantom Menace, not only as one of the model makers, but also as the puppeteer for R2-D2. He also makes a small cameo appearance as a mechanic in one of the pod race boxes. He also co-directed, co-wrote and co-starred in R2-D2: Beneath the Dome, a mockumentary narrating the career of "actor" R2-D2, which is included on the Special Features disc included with the DVD release of Star Wars: Episode II Attack of the Clones.
On Episode II, Don served as the supervisor of the droid unit, and also returned as the puppeteer for R2-D2. He also makes a small cameo appearance in the nightclub where Obi-Wan Kenobi and Anakin Skywalker follow Zam Wesell during their chase through Coruscant. He returned to the Star Wars saga for Star Wars: Episode III Revenge of the Sith, again as droid unit supervisor and R2-D2 puppetteer. He was also the R2-D2 operator, and C-3PO's wardrobe manager, for the 2005 mini-series Science of Star Wars.
Following his work on the prequel trilogy, Bies left ILM in 2004.
His wife also worked at Lucasfilm; She was a model builder for Episode I, as well as the costume designer for Dark Forces II.
- Star Wars: Attack of the Clones Scrapbook
- "Practical Magic: The Surprising Effects of the Prequels" — Star Wars Insider 160
- Star Wars: Build Your Own R2-D2 97
- "He's Worth a Lot to Me: Jeremy Bulloch, Inside Boba Fett" — Star Wars Insider Special Edition 2021
- "Industry, Laughter, & Magical Times" — Star Wars Insider 206