 After Poland regained independence, he became the first Polish Minister of Foreign Affairs, serving in the government of Jędrzej Moraczewski from 17 November 1918 to 16 January 1919.Afterwards he served as an advisior to naczelnik państwa, Józef Piłsudski; he was a member of the Polish National Committee in Paris (in 1919); and served as the Polish ambassador to Estonia (1920-1921).He took part in the Treaty of Riga negotiations and the commission for the delimitation of Poland's eastern borders.