Gilbert began his career in the computer industry at the beginning of the 1980s. With a signature drink called Graphic Basics he programmed on his Commodore 64 first simple games. He sold the tool to a company called Human Engineered Software, which also hired him after completing his computer science studies. He programmed arcade games for the C64, but none of them has ever been published, and the company has already completed half a year after his appointment the gates.
In 1985 he was given the opportunity to develop a game for Lucasfilm Games. Together with Gary Winnick he created the concept for Maniac Mansion and programmed for this game own engine: the Script Creation Utility for Maniac Mansion, better known by the acronym SCUMM.
1987 Maniac Mansion was released and became a huge success. The collaboration with LucasArts was permanent, and based on SCUMM many other graphic adventures have been developed, including Zak McKracken and Monkey Iceland I II
After the departure of LucasArts Gilbert was instrumental in the company Cavedog Entertainment ( Total Annihilation ), Humongous Entertainment and Entertainment Hulabee involved. The latter two were mainly specializes in the creation of computer games for children, Humongous Entertainment made a name for himself by games like Fritzi Fish or Putt-Putt, which, as Gilbert developed at LucasArts games, based on the SCUMM engine.
In 2004 he worked for the publisher Hothead Games again in a game for adults. It was a mix of adventure and role-playing game, which was released in 2010 under the name DeathSpank. In September 2010, Gilbert had betrayed that he was contacted by his former colleague and friend Tim Schafer and plan to go into the studio Double Fine Productions. In February 2012, Tim Schafer had confirmed that Gilbert had been up with him to work on a separate project. This was unveiled in May 2012 as The Cave and is the realization of an idea that Gilbert had developed 25 years ago - it was published on 22 January 2013.