During the occupation of Poland, he was active in the underground resistance. He was together with Mieczysław Moczar a co-founder of the organization Front Fighting for Our and Your Freedom, which after the uprising of Polish Workers Party transforms into its cells. Afterward, he worked in the apparatus of the Central Committee of the Polish Workers' Party. He then became a Representative of the Central Committee of the PPR for the Lublin region from June to July 1944.