Austro-Hungarian Navy
Ehm's father was a carpenter who served as an armorer and a bugler in the Austro-Hungarian Navy (KuK Kriegsmarine) during World War I. Ehm was born during his father's military service at Pula, a major Austro-Hungarian Navy port on the Adriatic near Trieste. He had a brother Hermann, born in 1913 and a younger sister Maria, born in 1921.