During World War II he was a partisan in the Peasants' Party Special Units and in 1943 joined Poland's Home Army.
Shortly after leaving the army in 1944, he made his debut as an actor in Rzeszów playing Jasiek in Stanisław Wyspiański's The Wedding.
At the end of November 1967, the National Theatre presented Adam Mickiewicz's 1824 play Dziady (Forefathers' Eve) directed by Dejmek.
[2] From 1969 to 1972 Dejmek was basically in exile and primarily worked outside Poland where he directed in the Nationaltheatret in Oslo, the Schauspielhaus in Düsseldorf, the Burgtheater in Vienna, and Giorgio Strehler's Piccolo Teatro in Milan.
His son, Piotr Dejmek (born 1953), became a noted television actor in Poland and later a film director and producer.