As well as the Sega download title, Gilbert is best known for his work on 90s PC adventure games for Lucasarts, including Monkey Island.
He wrote on his blog on Monday: "Now that The Cave is done and unleashed on an unsuspecting world (ok, we did do a bunch of PR, so it wasn't exactly unsuspecting), it's time for me to move on from Double Fine and plot my next move.
"So many games left to be designed.
"I want to thank all the amazing people at Double Fine for all their hard work on The Cave. It was a true pleasure to work with every one of them over the past two years. So much fun. I will miss them all. And of course to Tim for creating the opportunity to come there and make The Cave."
In the short term, Gilbert and DeathSpank co-creator Clayton Kauzlaric will focus on creating an iOS title called 'Scurvy Scallywags in The Voyage to Discover the Ultimate Sea Shanty: A Musical Match-3 Pirate RPG'.
The designer is also set to hold a keynote at PAX Australia.