He made his first trip to the Arctic on a sealer in 1882 and upon his return became curator of the natural history collection of the Bergen Museum. In 1888, with a party of five, he made a memorable journey across Greenland on skis, described in his First Crossing of Greenland (1890).
Conceiving a startling and much-derided plan for reaching the North Pole by drifting in the ice across the polar basin, he sailed to the Arctic in 1893 in the Fram, especially designed to resist crushing by ice. The Fram was anchored in the ice pack at lat. 83°59'N, drifted northward to 85°57', and later (1896) returned safely (although without having reached the pole) to Norway, as Nansen had predicted, by way of Spitsbergen. In the meantime, Nansen had left the ship in 1895 and with F. H. Johansen set forth to complete the journey to the pole by sledge. They were, however, turned back by ice conditions at lat. 86°14'N, the northernmost point to have been reached at that time.
When they were wintering (1895-96) on Franz Josef Land (now often called Fridtjof Nansen Land), members of the Jackson-Harmsworth expedition (see Jackson, Frederick George) chanced upon them and sent them home in one of their ships. Nansen's arrival in Norway was followed eight days later by that of the Fram, under Otto Sverdrup. Although neither he nor his ship had reached the North Pole, his expedition gave the world much new valuable information about the Arctic Ocean and the Arctic and made Nansen internationally famous. He had proved that a frozen sea lay around the Pole and filled the polar basin (see Arctic Ocean).
With his highly detailed information on oceanography, meteorology, diet, and nutrition, Nansen had laid the basis for all future arctic work. Farthest North, his account of this brilliant exploit, appeared in English translation in 1897, and the expedition's scientific material was published as The Norwegian North Polar Expedition (ed. by Nansen, 6 vol., 1900-1906). The Nansen Fund for scientific research was established in his honor. At the university in Christiania (now Oslo), he became professor of zoology (1897) and of oceanography (1908).
Nansen's career as a statesman began in 1905, when he worked for the peaceful separation of Norway from Sweden; his efforts were rewarded by his appointment as Norway's first minister to Great Britain (1906-8). In 1901 he had become director of an international commission to study the sea, and he made (1910-14) several scientific journeys, mainly in the N Atlantic.
In the years after World War I he added to his role of great explorer that of great humanitarian, becoming internationally renowned for his service to famine-stricken Russia as well as for his work in the repatriation of war prisoners. Appointed (1921) as League of Nations high commissioner for refugees, Nansen received the 1922 Nobel Peace Prize, and the League honored him by creating (1931) the Nansen International Office for Refugees, which won the 1938 Nobel Peace Prize. As a memorial to his father, Odd Nansen founded (1937) the Nansen Help to supplement the work of the Nansen International Office.
See biographies by his daughter, Liv (Nansen) Hoyer (1955), E. Shackleton (1959), J. M. Scott (1971), and R. Huntford (1999); P. Vogt et al., Nansen: Explorer, Scientist, Humanitarian (1962).