Gilfoyle is one of the important characters in Silicon Valley, the HBO comedy. We follow the birth and evolution of a computer start-up in Silicon Valley. We will discover all the traps and obstacles that can be found on the road of a very talented boss but also much too naive for this environment. Richard has developed a revolutionary compression algorithm and when he decides to launch a start-up rather than accept to sell his application to a billionaire, he will need all the help he can get. So he recruits several of the computer scientists living with him in a business incubator. Gilfoyle is one of them. He has the particularity to be a Satanist and to have a cold humor. He also has a friendship/competitive relationship with Dinesh, one of the other developers working on the project.