[5] From an early age Pakštas was fierce, militant and deeply patriotic: he despised the Russian czar and wanted to overthrow him and is known to have participated in the illegal distribution of Lithuanian publications.

In 1912, he passed the exams of six high school classes as an external student at St Catherine Gymnasium in Saint Petersburg.

In 1919, after returning to Lithuania, he worked as a liaison officer in the military missions of France, the United States and England.

From 1919 to 1923, Pakštas studied natural sciences at the University of Fribourg, Switzerland, and defended his doctoral thesis, Climate of Lithuania.

However, Pakštas focused on his scientific work as well: he determined the climatic zones of Lithuania and started doing systematic research on lakes.

In 1938, some Lithuanian public figures such as Professors Stasys Šalkauskis and Steponas Kolupaila even urged him to become a presidential candidate for President of Lithuania.

The Lithuanian interwar newspaper XX amžius wrote: Professor Pakštas and his wife took an evening train from Klaipėda to Gothenburg and went to America on a Swedish ship.

From 1954 to 1957, he also worked in the Library of Congress, Washington, D. C. In 1941, he established the Lithuanian Culture Institute in Chicago and served as its head until mid-1943.

Fictional protagonist geographer Feliksas Gruodis (played by Aleksas Kazanavičius) from the 2019 period drama film Nova Lituania, which was written and directed by Karolis Kaupinis, was heavily based on Pakštas and his political works.