Ernst married Princess Sofie Antonie Brunswick-Wolfenbhuttel in 1749 in Wolfenbhuttel, Braunschweig, Germany. Sofie (daughter of Ferdinand Albrecht Brunswick Wolfenbuttel, II and Antoinette Amalie Brunswick-Wolfenbhuttel) was born on 23 Jan 1724 in Wolfenbhuttel, Braunschweig, Germany; died on 17 May 1802 in Coburg, Saxe-Coburg-Gotha, Thuringia; was buried in St. Moritzkirche, Coburg, Saxe-Coburg-Gotha, Thuringia. [Group Sheet] [Family Chart]

1. Duke of Saxe-Coburg Francis Frederick was born on 15 Jul 1750 in Saxe-Gotha, Germany; died on 9 Dec 1806 in Coburg, Sachsen-Coburg-Gotha, Thuringia; was buried in Herz. Hofgarten, Coburg, Sachsen-Coburg-Gotha, Thuringia.
2. Prince of Saxe Karl Wilhelm Ferdinand was born on 21 Nov 1751 in Coburg, S-C-Gt, Thrn; died on 16 Feb 1757.
3. Princess of Saxe Friederike Juliane was born on 14 Sep 1752 in Coburg, S-C-Gt, Thrn; died on 24 Sep 1752.
4. Princess of Saxe Karoline Ulrike Amalie was born on 19 Oct 1753 in Coburg, S-C-Gt, Thrn; died on 1 Oct 1829.
5. Prince of Saxe Ludwig Karl Friedrich was born on 02 Jan 1755 in Coburg, S-C-Gt, Thrn.
6. Prince of Saxe Ferdinand August Heinrich was born on 12 Apr 1756 in Coburg, S-C-Gt, Thrn; died on 8 Jul 1758.
7. Prince of Saxe Friedrich was born on 4 Mar 1758 in Coburg, S-C-Gt, Thrn; died on 26 Jun 1758.