An experienced and capable soldier, Charles LeClerc began his military career as a volunteer in 1791 and within two years had risen to become a divisional chief of staff at the siege of Toulon. Following the revolutionary success there, he campaigned along the Rhine, in Italy and fought at Castiglione and Rivoli. In 1797, the newly promoted General de Brigade LeClerc married into Napoleon Bonaparte's family when he wed Pauline Bonaparte, with whom he had a child. Given staff postings in both the Army of Ireland, then the Army of England, LeClerc gained promotion to general de division, which allowed him to assist Napoleon Bonaparte in his bid for power. 

More military campaigns followed on the Rhine and in Spain and then in 1802 his brother-in-law gave him command of the expedition to restore San Domingo, now Haiti, to France.  He then headed the force sent to subdue Haiti, where François Dominique Toussaint L’Ouverture had established a virtually autonomous state. The French won several victories after severe fighting, and an agreement was reached. This was broken by LeClerc, who, acting on Napoleon’s secret instructions, had Toussaint seized by trickery and deported to France. The natives, led by Jean Jacques Dessalines and Henri Christophe, rose in revolt and expelled the French, who were weakened by an epidemic of yellow fever. LeClerc died of the fever. Apart from sound military thinking, LeClerc used brutality and deception to end the rebellion of General Toussaint L'Ouverture, whom he seized during a meeting and exiled to die in a French prison. But LeClerc' s triumph was short-lived as within a year he had died from yellow fever and the tide swung inexorably against French hopes on San Domingo.