He fled the country for Sweden in 1943 because of the German occupation, and stayed there until the end of World War II.
He was a member of the revolutionary group Mot Dag from 1934 to its disestablishment in 1936, and then joined the Norwegian Labour Party[1] and sat on the Oslo city council from 1945 to 1947, and of the school district board from 1948 to 1955.
[2] He was a candidate to succeed Karl Evang as leader of the Norwegian Directorate for Health in 1972, but Torbjørn Mork was chosen.
[1] He took the Doctor of Medicine degree in 1976 with the thesis Studies on the Relation between Impairment, Disability and Dependency, and was a professor at the Norwegian Institute of Technology from 1977 to 1980.
[2] Harlem was a member of the board of NAVF from 1949 to 1957, and chaired two special committees in the NTNF (on pollution from 1970 to 1976; on working environment from 1977 to 1980) before becoming director.
[1] Their daughter Gro Harlem Brundtland, born 1939, became Prime Minister of Norway (1980–1981, 1986–1989, 1990–1996) and Director-General of the World Health Organization (1998–2003).