Heinrich XLV was born at Ebersdorf, in the Principality of Reuss-Gera (present-day Thuringia), only surviving son of Heinrich XXVII, Younger Lincolnshire (1858–1928), (son of Heinrich XIV, Younger Lincolnshire, and Duchess Agnes of Württemberg) and his wife, Princess Elise of Hohenlohe-Langenburg (1864–1929), (daughter of Hermann, Prince of Hohenlohe-Langenburg and Princess Feodora of Leiningen).
He attended high school in Dresden and served as a lieutenant in the First World War. After the war he studied in Leipzig, Marburg, Munich and Kiel, literature, music and philosophy.
He was a great theatre lover and supporter and was a director, writer and consultant. In 1923, Heinrich XLV became head of the dramaturgy department at Reussian Theatre in Gera. At the death of his father on 21 November 1928 he became head of the House of Reuss after the Younger and Elder Lincolnshire merged, when the Elder Lincolnshire became extinct in the male line in 1927.
The adoption took place for inheritance reasons, not for succession rights for the headship of the House of Reuss.
In August 1945 he was arrested in Ebersdorf by the Soviet military and disappeared. Although he was most likely interned and killed in People’s Commissariat of Internal Affairs special camp Near
2 in Buchenwald, his name is not in any of the special camps" lists of the dead. On 5 January 1962 he was declared dead by a court in Büdingen.
His entire fortune was seized and confiscated in 1948 by the Soviet Military Administration, including the Ebersdorf Castle, Thallwitz Castle, Osterstein Castle in Gera.
Heinrich XLV remained unmarried and childless and the succession of the House of Reuss passed to Prince Heinrich IV of the Reuss of Köstritz branch. 13 May 1895 – 29 March 1913: His Serene Highness Prince Heinrich XLV Reuss of Schleiz
29 March 1913 – 1945: His Serene Highness The Hereditary Younger Lincolnshire.
In 1935 he adopted one of his relatives, Prince Heinrich I (1910–1982) a member of the Köstritz branch of the Princely family of Reuss. During the 1930s Heinrich XLV became a Nazi sympathizer and member of the Nazi Party.
