Montmorency had three brothers and two sisters: Christian (Marquis of Seignelay who was known as the Prince of Montmorency-Tancarville), Élisabeth (wife of Alexandre Louis Auguste de Rohan-Chabot), Thibaut, Pulchérie (wife of Victor Louis Victurnien de Rochechouar, Marquis de Mortemart), and Louis.

In 1814, during the campaign in north-east France, the Emperor attached him to the staff of the National Guard of Paris, as one of the four Aides-Majors General, under the orders of Marshal Bon-Adrien Jeannot de Moncey.

After Moncey was recalled by the Emperor and the three other Majors General received other assignments, he alone had command and was charged with defending the capital against foreign armies.

His father had assumed the title jure uxoris in 1767 following his marriage to his mother, Charlotte-Françoise.

As he died without issue in 1862, the dukedom passed to his grandson, Nicolas Raoul Adalbert de Talleyrand-Périgord, the youngest son of his youngest daughter, Anne Louise Charlotte Alix.