From 1942 onwards, he took part in Gray Ranks (Polish: Związek Harcerstwa Polskiego, ZHP), an underground resistance movement against the Nazi forces.

Stefan Klajbor, aka Paweł,[1] was the liaison officer of the Garrison Headquarters with the commander of the local Gray Ranks company in Bydgoszcz.

At the end of WWII, Stefan resumed his studies at the High School Nr.2 Nicolaus Copernicus in Bydgoszcz (Polish: II Liceum Ogólnokształcące w Bydgoszczy) and was graduated in 1946.

[2] During his studies (1949-1951), he worked professionally as a referendary at the Maritime Office in Gdynia (Polish: Urząd Morski w Gdyni).

For his realizations and activities, he received many decorations and orders, among which: He was also the general designer of the Selfa Housing Estate in Szczecin.