Ernst August was baptized on 15 October 1983 at Marienburg Castle, his godparents including Felipe VI of Spain and Constantine II of Greece.

[4] He also descends from Germany's last emperor, Wilhelm II, following whose abdication at the end of World War I the Hanovers also lost sovereignty over the Duchy of Brunswick, while retaining much of their continental personal property.

Instead, the younger Ernst August was put in charge, reportedly for negligence on part of his father,[7] at the initiative of the foundation's trustee Prince Michael of Liechtenstein.

Thirty of more than 1000 items were contributed by Elizabeth II, including the State Crown of George I, while Ernst August provided the king's famous Augsburg silver throne and other furniture dating to 1720.

[10] He had initially planned to allocate the funds in a foundation for the renovation and maintenance of Marienburg Castle; however, he was forced to use most of it to settle his father's debt, which, at the time, had been unknown to him, as he told a newspaper in 2019.

[17] Despite the dynastic tradition of obtaining the head of the House of Hanover's express, prior authorization for an heir's marriage in accordance with an 1836 Hanoverian house law (as Ernst August's father had done when marrying his sons' future mother in 1981),[18] the bridegroom's father declared his intention to withhold consent for his son's marriage to Ekaterina Malysheva,[17] reportedly in a dispute over family assets.

Her wedding dress was the work of Lebanese designer Sandra Mansour, and she wore a tiara that belonged to the former Kaiser Wilhelm II's only daughter, Princess Victoria Louise of Prussia.

[18][29] Nor is the title "Prince/ss of Great Britain and Ireland", re-claimed by the deposed House of Hanover in 1931, accorded by British sovereigns to members thereof born after 30 November 1917.