Swedish botanist and Antarctic explorer, renowned as the most travelled of the Swedish botanists of his era. Skottsberg was born in Karlshamn, southern Sweden, where his father was a head teacher. He studied at the University of Uppsala, and at the age of just 20 took part as botanist on the Swedish Antarctic Expedition led by explorer Otto Nordenskjöld from 1901 to 1903. The expedition's ship was wrecked in February 1903 and its passengers were forced to overwinter on Paulet Island before being rescued by an Argentinian ship. Though many of his specimens were lost, Skottsberg lived to tell the tale and wrote up his findings over the following years, achieving his doctorate in 1907. Later that year he was appointed lecturer and in 1909 became Keeper of the Herbarium at the Botanical Museum of Uppsala.

Prior to this employment, he once more headed south, leading the Swedish Magellan Expedition to the Falkland Islands, Tierra del Fuego, Chile, Juan Fernandez Islands, Patagonia and South Georgia (1907-1909). No botanical observations had ever been made in many of the areas and his reputation as a taxonomist was thereby established, as well as a lifelong interest in geographical distribution, especially in the Pacific region. A few years later he again led a Swedish expedition to Juan Fernandez Islands, Easter Island and Chile (1916-1917).

Skottsberg returned to the Juan Fernandez Islands in 1954-1955 and explored Hawaii in 1922, 1926, 1938 and 1948, interested in similarities between the floras of the two island groups. As well as these expeditions, he journeyed to study vegetation on every continent at some point, and spent prolonged periods boosting his ever-increasing knowledge at different herbaria, for instance visiting Kew four times. In 1915 he was commissioned to plan the botanical garden for the city of Gothenburg, of which he was appointed director after its completion in 1919. He stayed in this position for 29 years, all the while heading off on travels and writing more than 200 papers. He was simultaneously Professor of Botany at the University of Gothenburg from 1931 to 1947.

Skottsberg's interests in many different plant families appear diverse and possibly unconnected, but his ultimate aim was to make phytogeographic links. He elaborated on Sir Joseph Hooker's idea that the continents were not separated by sea in the past, using his findings from his Antarctic and sub-Antarctic explorations. For example, fossil plant remains (Jurassic and Oligecene) he discovered in Graham's Land led him to suggest that a warm-climate flora once occupied the area now glaciated; plants that later, in the Tertiary period, migrated northwards and became differentiated. He was also something of a conservationist, concerned over the ways human intervention threatened endemic species. In 1935, Juan Fernandez was declared a National Park thanks to Skottsberg's efforts, though he was pessimistic about solutions to the destructive tendencies of civilisation. He stood as Secretary of the International Commission for Preservation of Wild Life in the Pacific for 20 years from 1929.

In 1949 Skottsberg was elected President of the Royal Swedish Academy and in 1950 President of the Seventh International Botanical Congress. In the same year he was elected a foreign member of the Royal Society, and came to be honorary member of countless scientific societies in Europe, the Americas, Japan and New Zealand over the course of his career. He was awarded the Linnean Society of London's Darwin-Wallace Medal in 1958 and the Linnean Medal in 1959. Other posts he held included Secretary of the Royal Society of Science and Letters of Gothenburg (1924-1937) and Chair of the Botanical Society of Gothenburg (which he founded in 1919). His writings mainly concerned the flora and taxonomy of the places he explored, and included The Wilds of Patagonia (1911), three volumes of The Natural History of Juan Fernandez and Easter Island (edited from 1920-1956) and "Remarks on the Plant Geography of the Southern Cold Temperate Zone" in the Proceedings of the Royal Society of London (1960). Numerous plants are named in his honour, including the genera Skottsbergia Cardot (Ditrichaceae), Skottsbergiella Epling (Lamiaceae), Skottsbergiella Boelcke nom. illeg. (=Skottsbergianthus Boelcke) (Brassicaceae) and Skottsbergiliana H. St. John (Cucurbitaceae). Skottsberg married in 1909, and his wife, Inga (née Reuter) joined him in collecting on several trips and bore him three children.