He was baptised at Église Saint-Sulpice. He served in the First Company of Musketeers of the Garde ordinaire du Roi from 26 November 1753 to 2 March 1755, as enseigne à drapeau to the regiment of the Gardes-Françaises (1755–57), then as Enseigne à Pique (from 5 June 1757) and sous-lieutenant (23 December 1759) in the same regiment.
Antoine Galiot Mandat married Angélique Simone Boucher, daughter of a conseiller to the Parlement de Paris on 21 January 1758. They had two children – Alexandre, ensign to the regiment of the Gardes-Françaises, and a daughter married to a conseiller to the Parlement de Paris. Antoine's father split his fortune between his children on his death in 6 April 1762.
In 1789, he left the Gardes-Françaises, at the rank of captain or colonel retiré du service, according to La Chenaye-Desbois. He was also a knight of the ordre royal et militaire de Saint-Louis. He tried in vain to become a gentleman of the court, but had to renounce his place despite his annual rent of 180,000 francs.
In the pre-revolutionary period Marquis Antoine-Jean-Galiot de Mandat was loved by everyone in Les Pins, in the north east of Touraine, even by those who would soon lead Revolutionary efforts in the area. He is known in history as "a noble who embraced the revolutionary party" and thus his behaviour corresponded to that of his neighbours and peasants.
Other articles related to "1789":
... The new school was built for £2,076 12s 5½d, and opened in 1789 on a site closer to the High Street and the present Glynne Road.53°13′48″N 4°07′19″W / 53.230°N 4.122°W ...
... In 1789, a Volunteer Artillery Company was raised to augment the Troop of Horse and the nine Companies of the Regiment of foot ...