Hanssen participated on the first three of Roald Amundsen’s polar expeditions and was part of the five-man group that reached the South Pole as the first on 14 December 1911.
Helmer Julius Hanssen (originally written Hansen) was born 24 September 1870 at Bjørnskinn (now Andøy), Vesterålen, Nordland county. His father, Hans Andreas Jacobsen (1832–1914), was a farmer and fisherman and from 11 years of age Helmer combined farm work with fishing in Lofoten and Finnmark, north Norway, with his father. In the years 1894–97 he hunted small whales and seals in the arctic seas. In 1897 he married Kristine Augusta Josefine Berg (1876–1963) and the same year he gained his mate’s certificate in Kristiansund. He then participated as mate on Henry J. Pearson’s British expedition to Novaya Zemlya with the s/s Laura. While Laura was in Sandefjord prior to start, Hanssen met Roald Amundsen, who was preparing for the Belgian expedition with the Belgica to Antarctica. The following year Hanssen was the skipper of the sealer Elida before he sailed for five years on coastal and overseas routes, amongst others for the Vesterålen Steamship Company (Vesteraalens Dampskibsselskab). In 1915 he gained his skipper certificate.
Helmer Hanssen was engaged as mate on Roald Amundsen’s expedition through the Northwest Passage with Gjøa in 1903–06, after recommendation from Amundsen’s friend Fritz Zapffe in Tromsø. This started an 18-year long association with Amundsen. Hanssen and his wife now had a baby son. While Hanssen was away on the Gjøa expedition, he learned dog sledging from the Inuit, which was to be of great use on the South Pole expedition.
After Gjøa’s return home, Hanssen worked for the Customs in Tromsø, but he was given leave to participate as ice pilot on Amundsen’s next expedition in 1910–12. He now had three small children at home. The expedition was officially to go north, but went to the Antarctic instead. Hanssen was in the group which reached the South Pole on 14 December 1911 and his sledge carried the principal compass.