His father served in the Swedish Army as a judge-advocate but also worked as a civilian lawyer, farmer and assistant cantonal judge.

At Uppsala he learned from lecturers such as A.G. Högbom, who developed the concept of the geochemical carbon cycle[4] and Rutger Sernander, of the Blytt-Sernander Pleistocene sequence.

Von Post began working on a history of the development of the Mästermyr marsh on Gotland with Jakob Ljungqvist in 1902.

[3] This work led to the publication of the first modern pollen diagram in 1916, the same year that von Post presented his now famous lecture in Christiania, although the two pertained to different subject matter.

[7] Von Post discovered by accident a small canyon near Degerfors in 1923 which he then held was the elusive outlet of the Ancylus Lake.