He was born in Kristiania as a son of Gudmund Harlem, Sr. (1885–1918) and Olga Haug (1887–1942). He finished his secondary education in 1935, enrolled as a student at the University of Oslo in the same year, and graduated with the cand.med. degree in 1946. He fled the country for Sweden in 1943 because of the German occupation, and stayed there until the end of World War II.[1] In the autumn of 1945 he was the leader of the Norwegian Students' Society. He was hired as a physician at Statens Attføringsinstitutt in 1946, and was promoted to chief physician in 1953.[2]
He also became involved in politics. 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. He was also a member of the central committee of the Workers' Youth League from 1946 to 1949, and of the International Union of Socialist Youth board from 1946 to 1951. From 1949 to 1957 he was a deputy member of the Labour Party's central committee; he was deputy chairman of the Oslo branch from 1952 to 1957.[2]
After the end of his political career, Harlem returned to the Statens Attføringsinstitutt. He also doubled as assistant physician at Rikshospitalet from 1965 to 1966. In 1970 he was promoted to director of Statens Attføringsinstitutt, a position he held until 1977.[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. He rounded off his career as director of NTNF from 1980 to 1986, and then with two years as a general physician in Oslo. He died in March 1988.[2]