Born in the 20 April 1776 in the town of Saint-Julien-en-Genevois, then a part of Piedmont, Pacthod joined the King's Life Guards but France soon occupied his country and the French-speaking Pacthod rallied to the ideas of the French Revolution. He was elected lieutenant-colonel by the volunteers of the Mont-Blanc department and then sent to serve in the Siege of Toulon, where he was wounded seven times. He was deputy to the Chief of Staff of the French expeditionary force destined to Corsica and then, in January 1795, appointed to the military command of Marseille. He was holding this command when the family of General Napoleon Bonaparte, which had fled their native Corsica during the British occupation of the island, took refuge in the city. The Bonapartes had fled Corsica in order to escape possible retaliation from the British occupants and arrived destitute in Marseille. It seems that Pacthod showed little generosity towards the Bonapartes, a behaviour which Napoleon would never forgive. His career did advance quickly during the following years, seeing promotion to Brigadier General in May 1795, and was noted for his actions at the Battle of Alkmaar and Battle of Castricum.