Career
The Knight"s Cross of the Iron Cross was awarded to recognise extreme battlefield bravery or successful military leadership. Müller-Stöckheim joined the Kriegsmarine in April 1934. He served for a time on the battleship Schlesien, and was a training officer at the Naval Academy Mürwik (Marineschule Mürwik) in Flensburg-Mürwik.
He transferred to the U-boat force in April 1940, and made two patrols as 1st Watch Officer of U-123 under Karl-Heinz Moehle in early 1941.
In July 1941 Müller-Stöckheim took command of the IXC U-boat U-67 and made eight patrols, sinking thirteen merchant ships totalling 72,138 gross register tons (GRT), and damaging five more (29,726 GRT). Müller-Stöckheim was killed when U-67 was sunk on 16 July 1943 in the Atlantic Ocean by bombs from an Avenger torpedo bomber from the escort carrier United States Ship Core.