Stefan Jan Klajbor was born in
Bydgoszcz on 20 October 1924. He was the son of Jan, a railwayman, and Wanda, née Nowakowski. After graduating from elementary school, he studied at the
State High School of Humanities, located at 18/22
Grodzka Street (today's
High Seminary of Bydgoszcz Diocese). During
German occupation, he was enlisted as a worker: in 1941, he was sentenced to six months of labor camp for economic activity
sabotage. From 1942 onwards, he took part in
Gray Ranks (), an underground resistance movement against the Nazi forces. In May 1943, his group was responsible for the
Home Army garrison's communications in Bydgoszcz. Stefan Klajbor, aka
Paweł, During his studies (1949-1951), he worked professionally as a
referendary at the
Maritime Office in
Gdynia (). After graduation, he was employed for several months as a deputy construction manager at the
Municipal Construction department of Gdańsk, between 1951 and 1952. After that stint, Klajbor returned to
Bydgoszcz. ==Work in Bydgoszcz==