From 1949 to 1969, Kostetskyj was the editor of Ukraine and the World (Ukrainian: Україна і Світ, Ukraïna i svit), a journal of cultural, literary, scholarly, and political affairs published by Ilia Sapiha in Hannover, West Germany. With his wife, German poet and translator Elisabeth Kottmeier, Kostetskyj established the Na Hori (Ukrainian: На горі On the Mountain) publishing house in the mid-1950s, publishing several dozen books including Ukrainian translations of literary classics.