Bock joined already before the First World War, the Centre Party and was from 1919 to 1933 a member of the local council in Rottweil. He was in 1919 in the constituent assembly of the Free People's State of Württemberg. He co-worked in the formation of the new constitution. In the same year he was elected to the Parliament of Württemberg, where he stayed till 1933. From 1928 to 1933 he was chairman of the center faction in the parliament.
