Born in Paris, Labrouste was one of five children of , a lawyer and politician from Bordeaux and Anne-Dominique Gourg (1764–1851), daughter and granddaughter of cognac merchants. He entered the
Collège Sainte-Barbe as a student in 1809. He was then admitted into the second class and the Lebas-Vaudoyer workshop in the École Royale des Beaux Arts in 1819. In 1820, he was promoted to the first class. Competing for the Grand Prix, Labrouste was awarded second place (the Palais de Justice scored first) by
Guillaume-Abel Blouet in 1821. In 1823, he won the departmental prize and worked as a lieutenant-inspector (
sous-inspecteur) for the director
Étienne-Hippolyte Godde during the construction of the Saint-Pierre-du-Gros-Caillou parish in Paris. In 1824 Labrouste won the competition with a design of a Court of Appeals (Cour de cassation). In November, he left Paris for Italy, visiting Turin, Milan, Lodi, Piacenza, Parma, Modena, Bologna, Florence and Arezzo. In July 1835 in Paris he was present at the scene when
Giuseppe Marco Fieschi attempted the assassination of King
Louis-Philippe using a home-made, multi-barrel gun fired from an upstairs window. Although the King only received a minor injury, 18 people were killed, including Henri's father, Alexandre Labrouste. ==Stay in Rome==