Born in Gilly in the Vaud region of Switzerland in 1945, Keller studied graphic design at Ecal, graduating in 1965. He became a renowned graphic designer himself, representing his country at numerous international biennials and winning several prizes. He joined Ecal in 1995, transforming the school into one of the most highly regarded of its type in the world. Under Keller's direction, the school became renowned for its graphics, photography and industrial design departments. One of his innovations was to bring in international brands to set real-world briefs for students while generating income for the school, a practice that has since been adopted by other leading schools.