After the death of his elder brother Heinrich LX (1784–1833) he was the senior member of the Köstritz branch of the House of Reuss.

His sister Auguste Fredericka Espérance was the wife of Henry, Duke of Anhalt-Köthen.

After she died, on 11 May 1828, Heinrich LXIII married her sister Countess Caroline of Stolberg-Wernigerode (1806–1899).

From 1833 until his death, he was a member of the First Chamber of the Saxon parliament.

Among others, he owned estates in Klipphausen, Spreewiese and Klix.