He was born in Kristiania as a son of assisting secretary Jens Ingolf Evang (1873–1914) and Anna Beate Wexelsen (1875–1954).
[1] His sister Anne Beate married another civil servant, Karl Ludvig Bugge.
[1] He enrolled in medicine studies at the Royal Frederick University in 1924, and became a member of the revolutionary group Mot Dag in 1926 which had a strong[citation needed] standing among students.
He was elected chairman of the Norwegian Students' Society in 1931, while serving a prison sentence for conscientious objection.
He issued the 1934 book Rasepolitikk og reaksjon, and wrote with the purpose of medicinal and hygienic enlightenment in the publications Populært Tidsskrift for Seksuell Oplysning (which he edited) and Arbeidermagasinet.
He spent the war years organizing a health administration for Norwegians abroad, spending time in the USA as well.