Some years later, through the influence of her aunt, Charlotte-Jeanne Béraud de la Haye de Riou, marquise de Montesson, who had been clandestinely married to the Louis Philippe I, Duke of Orléans, she entered the Palais Royal as a lady-in-waiting to their daughter-in-law Louise Marie Adélaïde de Bourbon-Penthièvre, Duchess of Chartres as the wife of their heir Louis Philippe II, Duke of Chartres. She acted with great energy and zeal as governess to the daughters of the family, and was in 1781 appointed by the duke of Chartres to the responsible office of gouverneur of his sons, a bold step which led to the resignation of all the tutors as well as to much social scandal, though there is no reason to suppose that the intellectual interests of her pupils suffered on that account.
The better to carry out her ingenious theories of education, she wrote several works for their use, the best known of which are the Théâtre d'éducation (4 vols., 1779-1780), a collection of short comedies for young people, Les Annales de la vertu (2 vols., 1781) and Adèle et Théodore (3 vols., 1782). Charles Augustin Sainte-Beuve tells how she anticipated many modern methods of teaching. History was taught with the help of magic lantern slides and her pupils learnt botany from a practical botanist during their walks.
In 1789 Madame de Genlis showed herself favourable to the French Revolution, but the fall of the Girondins in 1793 compelled her to take refuge in Switzerland along with her pupil Mademoiselle d'Orléans. In this year her husband, the marquis de Sillery, from whom she had been separated since 1782, was guillotined. An "adopted" (actually natural) daughter, Stephanie Caroline Anne Syms, called Pamela, had been married to Lord Edward Fitzgerald at Tournai in the preceding 27 December. (Another "adopted" (actually natural) daughter, Hermine Syms, married Jacques Collard de Montjouy.) In 1794 Madame de Genlis fixed her residence at Berlin, but, having been expelled by the orders of Frederick William II of Prussia, she afterwards settled in Hamburg, where she supported herself for some years by writing and painting. After the revolution of 18th Brumaire (1799) she was permitted to return to France, and was received with favour by Napoleon Bonaparte, who gave her apartments at the arsenal, and afterwards assigned her a pension of 6000 francs.
During this period she wrote largely, and produced, in addition to some historical novels, her best romance, Mademoiselle de Clermont (1802). Madame de Genlis had lost her influence over her old pupil Louis Philippe, who visited her but seldom, although he allowed her a small pension. Her government pension was discontinued by Louis XVIII, and she supported herself largely by her pen.
Her later years were occupied largely with literary quarrels, notably with that which arose out of the publication of the Diners du Baron d'Holbach (1822), a volume in which she set forth with a good deal of sarcastic cleverness the intolerance, the fanaticism, and the eccentricities of the philosophes of the 18th century. She survived until 31 December 1830, and saw her former pupil, Louis Philippe, seated on the throne of France.
The numerous works of Madame de Genlis (which considerably exceed eighty), comprising prose and poetical compositions on a vast variety of subjects and of various degrees of merit, owed much of their success to advantageous causes which have long ceased to operate. They are useful, however (especially the voluminous Mémoires inédits sur le XVIII' siècle, 10 vols, 1825), as furnishing material for history.