After his strictly military upbringing, which he received together with his brothers on the Princes' Island and in the Princes' House at Plön Castle , Adalbert joined the Imperial Navy on May 31, 1894 and attended the Naval Academy and School (Kiel) to work as a naval officer to be trained. After completing his training, Adalbert undertook a few trips abroad, including to Brazil and represented Kaiser Wilhelm II at the courts in Beijing and Athens . At his father's request, he also received drawing lessons from the sea and landscape painter Poppe Folkerts. As a naval officer, he lived in a small house in the port of Kiel, the Villa Seelust . On August 3, 1914, Adalbert married Princess Adelheid of Saxe-Meiningen (1891-1971) , the marriage ceremony took place in Wilhelmshaven . Princess Adelheid, then 22, was a granddaughter of Duke George II of Saxe-Meiningen , the popular "Theater Duke". The marriage produced three children. Princess Adelheid's uncle, later Duke Bernhard III. , was married to Kaiser Wilhelm II's sister, Princess Charlotte .
During the First World War , Adalbert served first as a navigation officer on SMS Kaiser , then later joined the staff of the Second Admiral of the IV Squadron and was Commander of the light cruiser SMS Danzig from May 1917 , with which he also took part in Operation Albion . In March 1918 he took over command of the new SMS Dresden building (1917) until the end of the war. During the war, Empress Auguste Viktoria's mother entrusted her daughters-in-law with social and charitable tasks. Adelheid was instrumental in two naval convalescent homes. In July 1918, the homes for members of the naval forces and the marine corps in Berchtesgadenbe opened.
Adalbert, who was also a major in the Prussian Army , was a la suite of the 1st Foot Guards Regiment , the Grenadier Regiment "König Friedrich der Große" (3rd East Prussian) No. 4 and the 1st Grenadier Guards Landwehr - Regiments.