She was hastily married on 25 November 1755, by contract signed before Mr. Patu, notary in Paris, with Jacques Pelet de Beaufranchet, Seigneur d'Ayat (born 5 March 1728). The marriage was arranged by the inner circle of Madame de Pompadour. The Duke of Luynes and the Marquis de Valfons recorded that the Prince of Soubise and the Marquis de Lugeac received the task to find a husband for Marie-Louise O'Murphy and arrange her marriage. The intended husband was chosen with great care: well born, with a good name for the former "Petite maîtresse", young and good-looking. Beaufranchet, a good soldier and without fortune, obeyed the King's order.