On December 17, 1917, Przanowski joined Jan Kucharzewski's government as the Minister of Provisions. He later resigned along with the rest of the cabinet in protest against the Treaty of Brest-Litovsk.
In 1920, he was appointed as the Minister of Industry and Trade by Wincenty Witos. Stefan Przanowski was a supporter of the free market and liquidated the previously operating statist offices [pl]: coal, oil, grain. He was often referred to as “the pope of Polish liberalism”.
In honour of Stefan Przanowski’s merits, in 1921, the ministries decided to name the salt cave located in the Wieliczka Salt Mine, the Przanowski Chamber.[1]
In 1922, during the government crisis, Stefan Przanowski was appointed as Prime Minister of Poland. He was not able to create a cabinet due to objections from the Chief of State (Equivalent to President) Józef Piłsudski. Przanowski ran for the Sejm later in 1922 and lost, then withdrawing from politics.
From 1918 to 1930, Stefan Przanowski was chief executive officer of Norblin, Bracia Buch i T.Werner [de]. In 1934, he was appointed president and chairman of the supervisory board of Norblin, Bracia Buch i T.Werner in Warsaw.
Stefan Przanowski is noted among the most influential industrialists and economic activists; and retained independence from foreign capital. Przanowski was a member of the supervisory boards and investor representative boards of many industrial companies and banks. Some notable examples are:
Bank Polski (vice-chairman: today PKO Bank Polski, Poland's largest bank)
Bank Śląski (vice-chairman: today ING Bank Śląski, Polands second largest bank)
Bank Dyskontowski (deputy chairman: seized by the central government)
He lived in Warsaw at Aleje Ujazdowskie 36 (Kamienica pod Gigantami). In 1924, the Przanowski family acquired an estate of 600 hectares and a grand palace. The estate is located in Nowa Wieś near Starogard Gdański in Pomerania.[3]
He was married to Zofia Przanowska (born: Grabowska). The couple had a son Wojciech Przanowski, who was a soldier of the Warsaw Uprising and an engineer.[4] The couple further had a daughter Izabela Wasiak, a Polish language teacher, lector and underground publisher.
In 2022, on the initiative of the Prime Minister of Poland, Mateusz Morawiecki, the grave of Stefan Przanowski was renovated. The entire project was implemented by the Stare Powązki Foundation in cooperation with the Chancellery of the Prime Minister.
Ministrowie Polski Niepodległej 1918–1945, pod red. Marka Baumgarta, Henryka Walczaka i Adama Wątora. Szczecin: Wyd. Naukowe Uniwersytetu Szczecińskiego, 2001, s. 327–329, ISBN83-7241-146-8.
^M.P. z 1927 r. nr 258, poz. 706 „za wybitne zasługi w organizowaniu przemysłu obrony Państwa i wybitny udział w pracach nad utrwaleniem sytuacji finansowej kraju”.