His paternal grandfather, the Hereditary Prince Johann Leopold (1906–1972), had been heir-apparent to the sovereign Duchy of Saxe-Coburg and Gotha, but Johann Leopold's father, Duke Charles Edward, was the last prince of the House of Wettin to reign, abdicating on 14 November 1918 amidst the collapse of the German Empire at the end of World War I. Johann Leopold renounced his claim as the deposed dynasty's heir on 27 February 1932, 15 days prior to his non-dynastic marriage to Baroness Feodora von der Horst (1905–1991).
[1] The Headship of the Coburg Wettins would thus pass to Johann Leopold's younger brother, Prince Friedrich Josias, who dynastically married a countess of a mediatized family.
Before his death in 1954, Duke Charles Edward re-allocated the family's remaining fortune as an inheritance for their son and heir Andreas, Prince of Saxe-Coburg and Gotha.
[citation needed] Divorced from the baroness, Johann Leopold lived with his second wife, Maria Theresia Reindl, in Greinburg Castle, a Coburg property in Grein, Austria.
Ernst-Leopold had been born in Hirschberg in Silesia, but Hubertus's parents' marriage and his birth took place in Herrenberg in Württemberg.