First Czechoslovak Republic
After World War I, Klapálek became a commissioned officer and helped to establish the army of the newly-founded First Czechoslovak Republic. He served in Plzeň, Prague, Michalovce, and Uzgorod, where he met his future wife Olga Kosutova (born 8 March 1901). He then served in Milovice and at the Military Academy in Hranice.