While Kasner served in the military during World War II, little is known about Horst Kasner's wartime service; he was held as a prisoner of war at the age of 19. During his high school years he was a member of the Hitler Youth, with the last service position of a troop leader. From 1948 he studied theology, first in Heidelberg then in Hamburg. It was in Hamburg that he got to know and later married Herlinde Jentzsch, an English and Latin teacher, born on 8 July 1928 in Danzig (now Gdańsk, Poland) as the daughter of Danzig politician Willi Jentzsch.
