After the seizure of power in Germany by the Nazis in 1933, broadcasting director Ernst Hardt was dismissed but Strienz joined the S.A. and was engaged by the Berlin State Opera.
[1] In 1937 and 1938, he sang Sarastro in the first complete recording of Mozart's opera Die Zauberflöte (The Magic Flute) with the Berlin Philharmonic under Sir Thomas Beecham, and in 1943 Falstaff in the first complete recording of Nicolai's opera Die lustigen Weiber von Windsor (The Merry Wives of Windsor) under Artur Rother, also in Berlin, both of these major German roles with overpowering magnificence and grandeur of voice and interpretation.
He was also known for his renditions of the ballads Der Nöck (The Water Sprite) by August Kopisch and Die Uhr (The Clock) by Johann Gabriel Seidl, both set to music by Carl Loewe.
[2] Because of his great popularity, the Nazi regime called on him after the start of World War II to sing on the popular radio music show Wunschkonzert für die Wehrmacht (Request Concert for the Armed Forces), where he was particularly renowned for his rendition of Gute Nacht, Mutter (Good Night, Mother) by Werner Bochmann.
In the immediate post-war period, German broadcasters, especially in the Soviet occupation zone,[1] boycotted Strienz since his name was associated with Nazi propaganda of the war years.