During his earliest years, Peter climbed as second guide with his father (Grabi-Peter); then, as a mature adult, he guided climbers with his brothers, including his half-brothers, the twins, Rudolf and Hans (born 1874), as well as Christian Kaufmann (1872-1930). His Führerbuch makes it clear that he not only climbed the Wetterhorn (12,142 ft) and the Jungfrau (13,642 ft) more than a hundred times, but also made numerous ascents of the Schreckhorn, the Finsteraarhorn, and the Eiger (13,020 ft) as well as peaks in the Canadian Rockies and Selkirks.