He was the youngest child, but only son, of Ernst Frederick III, Duke of Saxe-Hildburghausen, by his third wife, Princess Ernestine of Saxe-Weimar.

Frederick succeeded his father Duke of Saxe-Hildburghausen in 1780, when only seventeen years old; because of this, his great grand uncle, the prince Joseph of Saxe-Hildburghausen, assumed the regency on his behalf, this regency only ended in 1787 at the death of Prince Joseph.

Until 1806 he was subject to the restrictions of the imperial debit commission, which had placed the duchy of Saxe-Hildburghausen under official administration, because of his predecessors' dissolute financial policy.

During his reign, along with his beautiful wife, Charlotte, cultural life in the small town reached its zenith.

When the last duke of Saxe-Gotha-Altenburg died without issue in 1825, the other branches of the house decided on a rearrangement of the Ernestine duchies.