He was born on 25 June 1869 in Lemberg (Lviv in present-day Ukraine), Kingdom of Galicia and Lodomeria (part of the Austro-Hungarian Empire), to father Wiktor, who worked as an architect,[1] and mother Maria (née Rawska), who also hailed from a well-established family of Lviv architects.

After graduating from secondary school he studied architecture at the Lviv Polytechnic (1888-1892) and subsequently at the Technical University in Vienna (1892-1894).

[2] Upon completion of his studies, he became an assistant to Oswald Gruber at the university (1894-1896) and at the same time he further continued his education under Karl König.

[4] In 1888, Sadłowski was delegated to design a new railway station for the city of Lviv, which became a turning point in his career as an architect.

He collaborated with many prominent architects and sculptors from Lviv at the time including Alfred Zachariewicz, Antoni Popiel and Edmund Zieleniewski who worked on the interior design of the railway station as well as its façade.