In 1792, Barras became a commissioner for the French Army, selling weapons to Philippe Rose. The year after, Barras became acquainted with captain Napoleon Bonaparte at the Siege of Toulon. In 1794, Barras became part of a conspiracy to overthrow Maximilien de Robespierre, who was executed during the Thermidorian Reaction. Barras was eventually appointed to command troops in defense of the National Convention.
On 13 Vendémiaire in 1795, royalist forces marched on the Convention. The Convention ordered Barras to take military action against the royalists, although Napoleon became the de facto leader during the battle. Barras ordered Napoleon to fire on the royalists with his cannon, ensuring a decisive victory for the Republic. Following this, Barras became the president of the Directory.
Barras would later help Napoleon marry the former's earlier mistress, Joséphine de Beauharnais, in 1796. In 1799 however, Napoleon overthrew Barras and the Directory, proclaiming himself First Consul of France.