He briefly acted as vice-premier in the government of Wincenty Witos (October–December 1923). From 1924, he resumed his journalist activities as editor-in-chief of the papers "Rzeczpospolita" ("The Republic", not to be confused with the modern newspaper of the same name) and "Polonia". He opposed the May Coup of Józef Piłsudski and the subsequent establishment of "Sanacja". In 1930, Korfanty was arrested and imprisoned in the Brest-Litovsk fortress, together with other leaders of the "Centrolew", an alliance of left-wing and centrist parties in opposition to the ruling government.