He finished his secondary education at Kristiansand Cathedral School in 1912, and graduated in physics from the Royal Frederick University.
He released the paper Hovedlinjer i filosofiens utvikling fra midten av det 19. århundre til nutiden in 1916, and was hired as a research fellow in philosophy in 1917.
Then, after Nazi Germany invaded Norway in 1940, Schjelderup became leader of the university's Aksjonsutvalget, a resistance committee.
[2] The staff Johannes Andenæs, Bjørn Føyn, Johan Christian Schreiner, Eiliv Skard, Anatol Heintz, Odd Hassel, Ragnar Frisch, Carl Jacob Arnholm, Endre Berner and Harald K. Schjelderup were sent to Grini concentration camp.
[1] After the war Schjelderup returned as professor, and helped build and consolidate the university's psychology studies.