Kléber was born in Strasbourg, where his father worked as a builder. He received, partly at Paris, training in architecture, but his opportune assistance to two German nobles in a tavern brawl obtained for him a nomination to the military school of Munich. Thence he obtained a commission in the Austrian army, but resigned it in 1783 on finding his humble birth in the way of his promotion.
On returning to France he received the appointment of inspector of public buildings at Belfort, where be studied fortification and military science. In 1792 he enlisted in the Haut-Rhin volunteers, and was from his military knowledge at once elected adjutant and soon afterwards lieutenant-colonel.
At the defence of Mainz (July 1793) he so distinguished himself that though disgraced along with the rest of the garrison and imprisoned, he was promptly reinstated, and in August 1793 promoted general of brigade. He won considerable distinction in the Vendéan war, and two months later was made a general of division. In these operations began his intimacy with Marceau, with whom he defeated the Royalists at Le Mans and Savenay. For openly expressing his opinion that lenient measures ought to be pursued towards the Vendéans he was recalled; but in April 1794 he was once more reinstated and sent to the Army of the Sambre-and-Meuse.
He displayed his skill and bravery in the numerous actions around Charleroi, and especially in the crowning victory of Fleurus (26 June 1794), after which in the winter of 1794- 1795 he besieged Mainz. In 1795 and again in 1796 he held the chief command of an army temporarily, but declined a permanent appointment as commander-in-chief. On 13 October 1795 he fought a brilliant rearguard action at the bridge of Neuwied, and in the offensive campaign of 1796 he was Jourdan's most active and successful lieutenant.
Having, after the retreat to the Rhine, declined the chief command, he withdrew into private life early in 1798. He accepted a division in the expedition to Egypt under Bonaparte, but was wounded in the head at Alexandria in the first engagement, which prevented his taking any further part in the campaign of the Pyramids, and caused him to be appointed governor of Alexandria. In the Syrian campaign of 1799, however, he commanded the vanguard, took El-Arish, Gaza and Jaffa, and won the great victory of Mount Tabor on 15/16 April 1799.
When Napoleon returned to France towards the end of 1799 he left Kléber in command of the French forces. In this capacity, seeing no hope of bringing his army back to France or of consolidating his conquests, he made the convention of El-Arish. But when Lord Keith, the British admiral, refused to ratify the terms, he attacked the Turks at Heliopolis, though he had only 10,000 men against 60,000, and utterly defeated them on 20 March 1800. He then retook Cairo, which had revolted from the French.
Shortly after these victories Kléber was assassinated at Cairo by a fanatic on 14 June 1800, the same day on which his friend and comrade Desaix fell at Marengo.
Kléber was undoubtedly one of the greatest generals of the French revolutionary epoch. Though he distrusted his powers and declined the responsibility of supreme command, there is nothing in his career to show that he would have been unequal to it. As a second-in-command he was not excelled by any general of his time. His conduct of affairs in Egypt at a time when the treasury was empty and the troops were discontented for want of pay, shows that his powers as an administrator were little -- if at all -- inferior to those he possessed as a general.
Ernouf, the grandson of Jourdan's chief of staff, published in 1867 a valuable biography of Kléber. See also: