In 1741, at the age of nineteen, Jeanne Antoinette was married to Charles-Guillaume Le Normant d'Étiolles, nephew of her guardian, who accepted the match and the large financial incentives that came with it. These included the estate at Étiolles (28 km south of Paris), a wedding gift from her guardian, which was situated on the edge of the royal hunting ground of the forest of Sénart. With her husband, she had two children, a boy who died the year after his birth in 1741 and Alexandrine-Jeanne (nicknamed "Fanfan"), born 10 August 1744. Contemporary opinion supported by artwork from the time considered the young Mme d'Étiolles to be quite beautiful, with her small mouth and oval face enlivened by her wit. Her young husband was soon infatuated with her and she was celebrated in the fashionable world of Paris.
As Mme d'Étiolles became known in society, the King came to hear of her. In 1745, a group of courtiers, including her father-in-law, promoted her acquaintance with the monarch, who was still mourning the death of his second official mistress, the duchesse de Châteauroux.
Jeanne Antoinette was invited to a royal masked ball at the Palace of Versailles on the night of 25 to 26 February 1745, one of the many fêtes given to celebrate the marriage of the Dauphin Louis de France (1729–1765) to the Infanta Maria Teresa of Spain (1726–1746). By March, she was the King's mistress, installed at Versailles in an apartment directly below his. On 7 May, the official separation between her and her husband was pronounced.