He was born at Limoges, and apprenticed to a silk merchant of Lyons. In 1776 he enlisted in a French regiment to serve in the American War of Independence, and after being invalided in 1784 he married and set up in business at Limoges. At the outbreak of the French Revolution he volunteered, and as a subaltern took part in the first campaigns in the north of France. His rise was even more rapid than that of Hoche and Marceau. By 1793 he had become a general of division, and was selected by Carnot to succeed Houchard as commander-in-chief of the Army of the North; and on 15-16 October 1793 he won the brilliant and important victory of Wattignies.
Soon afterwards he became a "suspect," the moderation of his political opinions and his misgivings as to the future conduct of the war being equally distasteful to the Committee of Public Safety. Warned in time by his friend Carnot and by Bertrand Barère de Vieuzac, he avoided arrest and resumed his business as a silk-mercer in Limoges. He was soon reinstated, and early in 1794 was appointed commander-in-chief of the Army of Sambre-et-Meuse. After repeated attempts to force the passage of the Sambre had failed and several severe general actions had been fought without result, Jourdan and his army were discouraged, but Carnot and the civil commissioners urged the general to a last effort, and this time he was successful not only in crossing the Sambre but in winning a brilliant victory at Fleurus (June 26, 1794), the consequence of which was the extension of the French sphere of influence to the Rhine, on which river he waged an indecisive campaign in 1795.
In 1796 his army formed the left wing of the advance into Bavaria. The whole of the French forces were ordered to advance on Vienna, Jourdan on the extreme left and Moreau in the centre by the Danube valley, Bonaparte on the right by Italy and Styria. The campaign began brilliantly, the Austrians under the Archduke Charles being driven back by Moreau and Jourdan almost to the Austrian frontier. But the archduke, slipping away from Moreau, threw his whole weight on Jourdan, who was defeated at Amberg and Wurzburg, and forced over the Rhine after a severe rearguard action, which cost the life of Marceau. Moreau had to fall back in turn, and, apart from Bonaparte's marvellous campaign in Italy, the operations of the year were disastrous. The chief cause of failure was the vicious plan of campaign imposed upon the generals by their government. Jourdan was nevertheless made the scapegoat of the government's mistakes and was not employed for two years. In those years he became prominent as a politician and above all as the framer of the famous conscription law of 1798.
When the war was renewed in 1799, Jourdan was at the head of the army on the Rhine, but again underwent defeat at the hands of the Archduke Charles at Stockach (March 25), and, disappointed and broken in health, handed over the command to Andre Massena. He resumed his political duties, and was a prominent opponent of the coup d'état of 18 Brumaire, after which he was expelled from the Council of the Five Hundred. Soon, however, he became formally reconciled to the new régime, and accepted from Napoleon fresh military and civil employment. In 1800 he became inspector-general of cavalry and infantry and representative of French interests in the Cisalpine Republic, and in 1804 he was made a marshal of France. He remained in the new kingdom of Italy until 1806, when Joseph Bonaparte, whom his brother made king of Naples in that year, selected Jourdan as his military adviser. He followed Joseph into Spain in 1808; but Joseph's throne had to be maintained by the French army, and throughout the Peninsular War the other marshals, who depended directly upon Napoleon, paid little heed either to Joseph or to Jourdan. After the Battle of Vitoria he held no important command up to the fall of the Empire. Jourdan gave in his adhesion to the restoration government of 1814, and though he rejoined Napoleon in the Hundred Days and commanded a minor army, he submitted to the Bourbons again after Waterloo. He refused, however, to be a member of the court which tried Marshal Ney. He was made a count, a peer of France (1819), and governor of Grenoble (1816). In politics he was a prominent opponent of the royalist reactionaries and supported the revolution of 1830. After this event he held the portfolio of foreign affairs for a few days, and then became governor of the Invalides, where his last years were spent. Marshal Jourdan was buried in Les Invalides.
He wrote Opérations de l'armée du Danube (1799); Mémoires pour servir a l'histoire sur la campagne de 1796 (1819); and unpublished personal memoirs.