He was made director of California's Scripps Institute of Oceanography (SIO) in 1936, initially for 3 years but the intervention of World War II meant he held the post until 1948. While there he developed the theory of ocean circulation known as Sverdrup balance, the first truly accurate description of the phenomenon. After leaving SIO, he returned home to become director of the Norwegian Polar Institute and continued to contribute to oceanography, ocean biology and polar research.
He was a member of the US and Norwegian Academies of Science and the Swedish Order of the North Star. A unit of volume flux bears his name.