Born in Grenoble, Alphand entered the École polytechnique in 1835 and continued his engineering studies at the prestigious École des ponts et chaussées in 1837. He began his career as an engineer in the coastal city of Bordeaux, working on improvements to the port, railways, and other infrastructure. It was in Bordeaux that Alphand met and earned the trust of Baron Haussmann, who was the Prefect of the Gironde province. In 1854, the year after Haussmann was promoted to the powerful role of Prefect of the Seine (Paris) by Napoleon III, Haussmann hired Alphand as chief engineer of the Bois de Boulogne, a role which soon expanded into director of the newly formed parks department (Service des Promenades et Plantations), and later into an all-around director of public works. Under Napoléon III, Alphand participated in the renovation of Paris directed by Baron Haussmann between 1852 and 1870, in the company of another engineer Eugène Belgrand and the landscape architect Jean-Pierre Barillet-Deschamps. He created walks, parks and gardens designed to embellish and sanitize Paris. He also remodeled the Bois de Vincennes and Bois de Boulogne.