Jabłonowski, born in Gosslershausen (Jabłonowo Pomorskie), West Prussia (today Poland), graduated from military academy in Poznań.
Before the war, he served in the HQ of Okrągu Korpusu nr VII under gen. Tadeusz Kutrzeba, and in 1938 was the officer in charge of the special forces section.
During that time, he lived mostly in Toruń, although every few months he traveled to Warsaw for meetings with commanders of AK (Stefan Rowecki and Tadeusz Komorowski).
He was involved in the spying on the Peenemünde Nazi rocket facility, as one of the links between Polish operatives in the field, AK HQ, and through them, the Western Allies.
Released in 1947, he refused to join the communist Armia Ludowa, escaped through Sweden to the United Kingdom (where the Polish Government in Exile promoted him to Lieutenant Colonel), then emigrated to Toronto, Canada, where he lived the rest of his life.