[2] Saalwächter served on Hannover in 1910 and later on Westfalen as Flaggleutnant to Vice Admiral Hugo von Pohl, commander of the I. Marine-Geschwader.

On 1 April 1915 during World War I, Saalwächter became Flaggleutnant on Friedrich der Grosse, the flagship of the High Seas Fleet.

Saalwächter was named Commanding Admiral of Naval Station North Sea at Wilhelmshaven, one of the highest positions in the Kriegsmarine at the time, on 28 October 1938.

[2] On 2 March 1939, Saalwächter sent a report to the Naval High Command in which he openly discussed the acquisition of bases in Norway.

The report stressed both the dangers to Germany of British dominance in Norwegian waters and the favourable change in the geo-strategic position that a German occupation of Norway would bring about.

[2] Beginning in summer 1940, Saalwächter led German surface operations in the North Atlantic and the English Channel.

In 1940, he directed E-Boat forces against British shipping during the Kanalkampf phase of the Battle of Britain in support of the Luftwaffe.

[2] He was convicted by a Soviet military tribunal of war crimes on 17 October and executed by firing squad in Moscow on 6 December.