Born at the Palace of Versailles, he was one of seven children born to his parents, and their only son to live past the age of 5. At the age of 8, on 30 June 1704, he was baptised. Held at Versailles, King Louis XIV had Mary of Modena as the guest of honour at the ceremony; Mary was the widow of the exiled King James II of England. Louis was often described as being "hideous"; he was humpbacked and very unattractive. At the age of 13 his father died in Paris and Louis Armand succeeded to the Conti title and wealth, although there was no real principality. On 1 January 1711, Louis Armand was made a knight of the Order of the Holy Spirit. On 9 July 1713, Louis Armand married his maternal first cousin, Louise Élisabeth de Bourbon, known as Mademoiselle de Bourbon. Another proposed bride was her sister, Louise Anne de Bourbon. Louise Élisabeth was the daughter of Louis III, Prince of Condé and Louise-Françoise de Bourbon, a legitimised daughter of King Louis XIV and his famous mistress, Madame de Montespan. The event, also took place at Versailles and was part of a double marriage; on the same day, his oldest sister, Marie Anne de Bourbon, married Louis Henri I, Prince of Condé, known as the Duke of Bourbon. In the end, Louise Élisabeth's brother Charles, Count of Charolais, even proposed to Charlotte Aglaé, who is said to have considered the proposal but refused. Charlotte Aglaé herself married the Duke of Modena in 1720, in the presence of Louis Armand and Louis Élisabeth. The marriage of Louis Armand and Louise Élisabeth would later become stormy. . Louise Élisabeth was known to have been unfaithful to her husband, a liaison with the handsome Philippe Charles de La Fare was well known at court. In August 1716, Louis Armand caught Smallpox; it was Louise Élisabeth who would nurse him until his recovery. Louise Élisabeth later caught the illness herself but survived the disease. It was at this time that Louis Armand found out about Louise Élisabeth's affair with Monsieur de La Fare. He is reported to have hurt his wife to the point that she had to see a doctor on two separate occasions. Louise Élisabeth stayed at the Palais Bourbon which was her mothers private home in Paris. She also stayed at a convent in the capital. At the birth of their second son in 1717, Louis Armand said to her that he did not care for the child as he could not have been his; in turn, the proud Louise Élisabeth replied that she did not care for the child either because he was his. Louise Élisabeth and Louis Armand had to go to many court hearings in Paris. In 1725, she consented to return to the Prince of Conti, who had her confined to the Château de l'Isle-Adam. She was able later, however, to convince him to allow her to return to Paris in order to give birth to her daughter. It was while in Paris she gave birth to their only daughter Louise Henriette. He was treated with great liberality by King Louis XIV, and also by the Regent, Philippe II, Duke of Orléans. Louis Armand was a prominent supporter of the financial schemes of John Law, by which he made large sums of money. It was during the Regency of 1715 - 1723, Louis Armand was appointed a member of the Regency council itself as well as a member of the Council of War. In April 1717 he received the government of the Poitou region of France. This appointment came with a wage of 45,000 Livres. He served under Marshal Villars in the War of the Spanish Succession, but he lacked the soldierly qualities of his father. Louis Armand died at the Hôtel de Conti in Paris due to a "chest swelling".
Titles, styles, honours and arms
Louis Armand was also the Count of Alais, Beaumont-sur-Oise and of Pézenas; he was also the Duke of Mercœur. He also owned the Lordship of L'Isle-Adam.
Titles and styles
10 November 1695 - 22 February 1709: His Serene Highness the Count of La Marche
22 February 1709 - 4 May 1727: His Serene Highness the Prince of Conti