In 1920, Cieszyn Silesia was divided between Poland and Czechoslovakia by the decision of Spa Conference, in which Kiedroń was present as a Polish delegate. His hometown and the workplace fell to Czechoslovakia and Kiedroń left the Zaolzie area, as he was an active pro-Polish activist; and stayed in Poland, where worked in Upper Silesia and Warsaw. In 1923-1925 he was the Minister of Industry and Trade in the government of Władysław Grabski.