In 1683, he assisted the Imperialists in Hungary, and while there, he wrote some letters in which he referred to King Louis XIV as le roi du théâtre; because of this, and because of an early engagement at the side of the Turks, in 1685, on his return to France, he was temporarily banished to Chantilly.

His scandalous philandering and debaucheries caused tension and distance within the family, and earned him the nickname of le Grand Conti.

[3] He failed to obtain military assistance from the Swiss, and by the King's command, yielded the disputed territory to Marie d'Orleans, although the courts of law had decided in his favour.

In 1697, King Louis XIV offered him the Polish crown, and by means of bribes, the Abbé de Polignac secured his election.

Conti started rather unwillingly for his new kingdom, probably, as the Duke of Saint-Simon remarks, owing to his affection for Louise-Françoise de Bourbon.

But the misfortunes of the French armies, during the earlier years of the War of the Spanish Succession, compelled the King to appoint Conti, whose military renown stood very high, to command the troops in Italy.

Conti married Marie Thérèse de Bourbon, aged 22, who was the daughter of Henri Jules, Prince of Condé and Princess Anne Henriette of the Palatinate.