 In 1956 von Gunten became a member of the Swiss Mount Everest-Lhotse expedition, where he was responsible for the food and catering.On April 6, 1956 he succeeded in the Khumbu area together with the Sherpas Lobsang and Gyalsen the first ascent of today often visited Island Peak.Von Gunten reached the summit of Mount Everest together with the photographer Dölf Reist as the second team of this expedition, one day after the ascent by Jürg Marmet and Ernst Schmied.