Gerschwiler made his international debut at the 1939 European Championships, where he placed 5th. Between 1939 and 1947, no international skating competitions were held, due to World War II. Gerschwiler had been living in England with his uncle and coach Jacques Gerschwiler when the war broke out. When his uncle was called home to Switzerland, Gerschwiler stayed with Cecilia Colledge's family. He spent the war years working as a factory worker and fire watcher and was able to practice skating only once a week.