Promoted to Oberleutnant zur See on 1 April 1939, he reported for submarine training in October 1939, after the outbreak of World War II. On graduation, from December 1939 he served as second watch officer on, commanded by Otto Kretschmer. During his tour on U-23, he completed three successful patrols, during which the boat sank five ships for a total of 27,000 tons, as well as one destroyer. His fourth patrol on U-23 was under the command of Commander Beduhn, after which he was posted as first watch officer to the new U-93, commanded by Claus Korth.
U-331
On 31 March 1941, he was given command of a new Type VIIC boat,. The boat left Kiel on 2 July 1941, patrolling out into the mid-Atlantic Ocean as far as the Azores, before arriving at Lorient, France on 19 August. After sailing from Lorient on 24 September, and making the difficult passage into the Mediterranean Sea, on 10 October the boat engaged three British tank landing craft off Sidi Barrani, Egypt. Inflicting slight damage with her deck gun, the attack was broken off after U-331 was hit by 40 mm shells, which wounded two men and damaged the conning tower. The following day the boat arrived at Salamis, Greece. Departing Salamis on 12 November 1941, the boat was tasked with landing seven men of the Lehrregiment Brandenburg east of Ras Gibeisa, on a mission to blow up a railway line near the Egyptian coast. After completing this important task, Von Tiesenhausen was given free movement to patrol and attack Allied targets along the Egyptian coast. On 25 November 1941, north of Sidi Barrani, U-331 fired three torpedoes into the British . As the ship rolled over, her magazines exploded and she quickly sank with the loss of 861 men, while 395 were rescued. U-331 returned to Salamis on 3 December, where Von Tiesenhausen was promoted to Kapitänleutnant and awarded the Knight's Cross of the Iron Cross. Her next five patrols passed without incident or further sinkings, as she patrolled from Salamis to La Spezia, Italy. On her tenth patrol, U-331 was sunk on 17 November 1942, north of Algiers, during "Operation Torch". She had been badly damaged after being attacked by a Lockheed Hudson bomber and signalled surrender, but was attacked and sunk by a Fairey Albacore torpedo-bomber from the British aircraft carrier. Of her crew 32 were killed and 17 survived, including von Tiesenhausen.
