John Andrén was born in Ystad in 1897.
In 1916 he graduated from the Upper Secondary School in Malmö. Two years later he was commissioned in the Army and accepted as an officer in the reserve. In 1939 he was appointed a Captain in the cavalry. He studied law in Stockholm, but was content with a lower degree. This degree was, however, to be useful since, in 1930, it brought him an appointment at the Royal Library.
In the twenties he divided his time between studies, travels and bibliophilic expeditions. In 1932 he passed a course qualifying him for a librarianship, and in the same year he was appointed chief supervisor of the Royal Library reading room. In the following year he worked at the Croydon Public Library in London, and followed work at the British Museum for two months. He then studied at University College, London, for two years.
The Second World War interfered with the comfortable habits of the travelling gentleman, and the nation requested the service of the cavalry captain. From April 1940 to October 1945 he served as quartermaster with the Second Regiment of the Army Service Corps (T2) in Skövde; he was also head of the legal department there, and officer of archives etc. After the war he remained faithful to the military profession, working in the capacity of advicer with the Central Bureau of Conscription (Centrala Värnpliktsbyrån ) from 1945 to1953; he was manager there from 1953 to 1962. He died in 1965.