Sella was born in Biella in the foothills of the Alps and acquired his interest in Alpinism from his uncle, Quintino Sella. He made a number of significant climbs in the Alps, including the first winter ascents of the Matterhorn and Monte Rosa, and the first winter traverse of Mont Blanc. He took part in several expeditions further afield, including three to the Caucasus (where a peak now bears his name), to Mount Saint Elias in Alaska, to the Rwenzori in Africa, and the 1909 expedition to K2 and the Karakoram. The latter three expeditions were in the company of Luigi Amedeo, Duke of the Abruzzi. Sella continued to climb into his old age, and made his last attempt on the Matterhorn at seventy six. The attempt failed when one of his guides was injured in an accident.