He was born in Lensahn the son of Hereditary Grand Duke Nikolaus of Oldenburg (1897–1970) and his first wife Princess Helena of Waldeck and Pyrmont (1899–1948).
Eutin Castle in Schleswig-Holstein is a museum owned by a family foundation set up by Duke Anton-Günther.
According to his obituary issued by the family his ancestral titles (however not all part of his official German surname) were: HRH The Duke of Oldenburg, Heir in Norway, Duke of Schleswig, Holstein, Stormarn, Dithmarschen and Oldenburg, Prince of Lübeck and Birkenfeld, Lord of Jever and Knyphausen.
Duke Anton-Günther was married to Princess Ameli of Löwenstein-Wertheim-Freudenberg (1923-2016) at Kreuzwertheim on 7 August 1951.
They have two children: The Duke and the Duchess lived at Güldenstein Manor, Harmsdorf, Schleswig Holstein.