He became aide-de-camp to Marshal Richelieu, whom he followed through the Hanoverian campaign of 1757 to his government at Bordeaux in 1758; and at the age of twenty-five he was sent to St Petersburg as secretary of legation.
Here he witnessed the coup d'état which seated Catherine II of Russia on the throne, and thus obtained the facts noted in Anecdotes sur la révolution de Russie en 1762.
Catherine made repeated efforts to secure the destruction of the manuscript, which remained unpublished until after the empress's death.
The later years of his life were spent chiefly in Paris, where he held an appointment in the Foreign Office and went much into society; but he visited Germany and Poland in 1776.
See also a notice by Eugène Asse prefixed to an edition (1890) of Rulhière's Anecdotes sur le Maréchal de Richelieu; Sainte-Beuve, Causeries du lundi (vol.