Political career
After being liberated from Buchenwald, Čepička returned to his hometown of Kroměříž, where he headed the city administration between 1945 and 1946. From June 1946 until May 1948, he represented the KSČ in the Constituent National Assembly. Around this time, Čepička also married Marta Gottwaldova (1920–1998), the daughter of KSČ Chairman Klement Gottwald, who would soon become Prime Minister and then President.
At the end of 1947, Čepička joined the government as Minister for Domestic Trade. After the coup d'état of February 1948, he became Minister of Justice; in this position, he introduced a number of reforms of the Czechoslovak judicial system and legal acts aimed at securing the political power of the KSČ. Between 1949 and 1950, Čepička also headed the State Office for Church Affairs, and between 1951 and 1954, he was a member of the Presidium, the Political Secretariat and the Political Bureau of the Central Committee of the KSČ. He belonged to the so called "big seven" of party and state leaders, along with President Gottwald, Prime Minister Antonín Zápotocký, Central Committee Secretary Antonín Novotný, Minister of the Interior Václav Nosek, Minister of Foreign Affairs Viliam Široký and Minister of Information Václav Kopecký.
Čepička served as Minister of Justice until 1950, when he replaced Ludvík Svoboda as Minister of National Defence. In this position, he led a radical reorganization and expansion of the Czechoslovak Army: in 1950, a decision was taken to expand the strength of the army in peacetime from 170 000 to 250 000 men, and to 700 000 in times of war. The army administration was also restructured and modelled after the Soviet Army, and in 1954, the Czechoslovak Army was officially renamed the Czechoslovak People's Army. A large-scale redeployment of military units along the western border of Czechoslovakia also took place; according to historian Karel Kaplan, Čepička was personally ordered by Joseph Stalin to prepare the Czechoslovak Army for an incursion into Western Europe in case of a possible military confrontation.
As Minister of Defence, Čepička proposed the construction of the Hotel International Prague, and envisioned a monument to the newly formed Fourth Czechoslovak Republic that would reinforce ties with the Soviet Union.
