Glaessner was born in Aussig in the former Kingdom of Bohemia of the Austro-Hungarian Empire (now Ústí nad Labem in the Czech Republic).
[1] In 1932, he moved to Moscow and began working in petrogeology at the State Petroleum Research Institute until 1934.
Glaessner married Tina Tupikina in 1936, and moved back to Vienna in December late 1937.
Of Jewish descent on his father's side, he was arrested on 19 March 1938 but released to work at the Anglo-Iranian Oil Company (now British Petroleum) in London.
Later in 1938, he moved to Port Moresby, Territory of New Guinea (then under Australian control), where he worked for joint oil exploration companies until 1950.