Louis XVII was the younger son of King Louis XVI of France and Queen Marie Antoinette. His older brother, Louis Joseph, Dauphin of France, died in June 1789, a little over a month before the start of the French Revolution. At his brother's death he became the new Dauphin, a title he held until 1791, when the new constitution accorded the heir apparent the title of Prince Royal.

Marie Antoinette was the last queen of France prior to the French Revolution. She was born an archduchess of Austria, and was the penultimate child and youngest daughter of Empress Maria Theresa and Emperor Francis I. She became dauphine of France in May 1770 at age 14 upon her marriage to Louis-Auguste, heir apparent to the French throne. On 10 May 1774, her husband ascended the throne as Louis XVI and she became queen.