(3 February 1775, Strasbourg - 29 February 1848) was a French general, painter, and lithographer. His memoirs have frequently been republished and his name is engraved on the Arc de Triomphe.
He studied painting in the studio of Pierre-Henri de Valenciennes, alongside Jean-Victor Bertin, but left the studio to volunteer in the Compagnie des arts de Paris in 1792. He received his baptism of fire in the battle of Valmy later that year. He became a sergeant in the 1st Arsenal battalion and in 1793 moved to the artillery at La Fere, assisting in the sieges of Landrecies, Le Quesnoy and Valenciennes. At Valenciennes he became aide-de-camp to general Jacob then, as a lieutenant on attachment to the engineers, took part in the 1794 Holland campaign and the 1795 campaign.
Called to the depot in 1798, he succeeded brilliantly in his exams and was made a captain on attachment to the engineers. He became aide-de-camp to marshal Berthier in 1800, a post he retained until 1812 and in which he took an active part in practically all of the Napoleonic campaigns. He was wounded and captured in Spain. He was promoted to full captain after Marengo and chef de bataillon after Austerlitz, also become a knight of the Legion d'honneur and a colonel at the Siege of Saragossa.
The German campaign of 1806 brought him to Munich, where he visited the workshop of Alois Senefelder, the inventor of lithography. Lejeune was fascinated by the possibilities of the new method and whilst there he made the drawing on stone of his famous Cossack (printed by C. and ~f. Senefelder, 1806). Whilst he was taking his dinner, and with his horses harnessed and waiting to take him back to Paris, one hundred proofs were printed, one of which he subsequently submitted to Napoleon. The introduction of lithography into France was greatly due to the efforts of Lejeune.
In 1812, during the French invasion of Russia, he was made general de brigade and chief of staff to Davout. Frostbitten on the face, Lejeune left his post during the retreat from Russia and was arrested on the orders of Napoleon. Freed in March 1813, Lejeune was then sent to the Illyrian provinces, before rejoining the army under the orders of marshal Oudinot, becoming his chief of staff. During the Saxony campaign, Lejeune was present at the Battle of Lutzen (1813), the crossing of the River Spree and at Bautzen. He was made an officer of the Legion d'honneur and a commander of the Order of Maximilian of Bavaria. At the battle of Hoyersverda, when Below's corps wiped out the 12th corps formed up in square on the plain, Lejeune (at risk of being kidnapped) ventured into the enemy lines with one battalion, general Wolf's cavalry and six 12 pounder guns. He thus broke the whole of the Prussian artillery and saved marshal Oudinot and his army. Wounded several times and lastly at Hanau, he was authorised to leave the army in November 1813 after more than 20 years' service. After his departure from the army, he devoted himself to painting.