 From 1938, he was a member of the Polish parliament (Sejm) as a member of the parliamentary group Camp of National Unity (OZN).In September 1939, Żenczykowski took part in the defence of Warsaw.After escaping from German captivity, he became an organiser and president of the conspiracy organisation Związek Odbudowy Rzeczypospolitej (ZOR) (Union for the Reconstruction of the Commonwealth).