Hase was born in Gut Wangern, Breslau, Silesia, Prussia, Germany[1][2] (now Gmina Żórawina, Poland).

His father, Günther von Hase (1881–1948) was a Prussian major and a police officer from 1920 to 1934, ending his career as a Oberst der Landespolizei and Stabschef in Berlin.

[3] He entered a military career as a Fahnenjunker of the Artillerieregiment 19 Hannover / Celle, studying at the Kriegsschule Potsdam in 1936/37.

[1] Hase served in the Wehrmacht in World War II on fronts in Poland, France, Russia (where he was wounded in 1942), and Italy.

[3] After his uncle Paul von Hase participated in the 20 July plot and was executed,[4] he was dismissed from the Generalstab and sent to Schneidemühl, now in Poland.

[1] Hase attended a school for diplomats in Speyer in 1951,[1] which at the time accepted students without a university background.