Gauchat studied at the Kunstgewerbeschule Zürich where he later became a teacher. He also studied in Munich. After his studies he worked for some time as a lithographer. He then became a freelance designer of books, posters (with Bally as his most famous client), stamps, industrial and general advertising. In 1941 he was the founder of the Swiss Poster of the Year competition, which still exists today. After WW2, the Swiss National Bank held a competition for new banknotes, which Gauchat won with his beautiful 50, 100, 500 and 1000 Swiss franc notes (Hermann Eidenbenz won for the 10 and 20 franc notes). These symbolized values like fertility and motherhood, love of one’s neighbour and, rather less optimistically, death. It took a long time before the notes were printed (1956–57) and it is not certain if he ever saw them before he died in 1956.