Marie Brûlart de La Borde was the daughter of Nicolas Brûlart, marquis de La Borde, and his wife, Marie Bouthillier. In 1704 she married Louis Joseph de Béthune, marquis de Chârost (1681–1709), who was killed fighting against the British forces of the Duke of Marlborough at the Battle of Malplaquet, four days after the marquise gave birth to their only child: Marie Therese de Béthune-Chârost (1709–16), who died young. In 1735, she replaced the duchess de Boufflers as dame d'honneur of the queen: her sister-in-law the duchess de Béthune had been one of the twelve original dame du palais appointed to the queen in 1725. The position of dame d'honneur was the second in rank among the queen's female courtiers. From 1741, however, the first ranked position of surintendante was left vacant, which made her the highest ranked of all ladies-in-waiting for the duration of her time in the position. 
The marquise de Chârost remarried as her second husband (and his second wife) Charles Philippe d'Albert (1695–1758), the fourth duc de Luynes. Her husband left memoirs of the couple's life at court, leaving many interesting observations of the royal family, and of the king's mistress, Madame de Pompadour, whom the duke and duchess appear to have grown to respect over a period of time, though this grudging admiration did not affect the duchess's friendship or loyalty to Queen Marie Leszczyńska. Madame de Luynes died aged 79, and was the mother, by her second marriage, of Marie Charles Louis d'Albert, duc de Chevreuse (1717–1771).