He was originally a French diplomat in Philadelphia from 1793 to 1796, before returning to Paris to make a reconciliation, between the two countries after the Quasi-War, that led to the Treaty of Mortefontaine.
He expressed strong criticism, when the U.S. resumed trade relations with the parties in Haiti freed by the black general Jean-Jacques Dessalines, at the failure of the expedition to Saint-Domingue.
During the Saint-Domingue expedition, he struggled to ensure adequate supplies to the military, but quarreled with Charles Leclerc.
On 1 October 1802, Louis-Andre Pichon wrote to the U.S. government to reassure them, when the Spanish intendant of New Orleans decided to terminate the offloading of U.S. merchants in the port, which was French property, following a secret treaty in 1800.
He was recalled to Paris September 15, 1804, reportedly for failing to thwart the marriage of Jérôme Bonaparte with an American, Elizabeth Patterson, but also for frankness.