He began his career as an engineer in the coastal city of Bordeaux, working on improvements to the port, railways, as well as other infrastructure.

In 1854, the year after Haussmann was promoted to the powerful role of prefect of Seine in Paris by Emperor 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) in 1855, as well as later into an all-around director of public works.

[1] Under Napoleon III, Alphand participated in the renovation of Paris directed by Baron Haussmann between 1852 and 1870, in the company of engineer Eugène Belgrand and the landscape architect Jean-Pierre Barillet-Deschamps among others.

Among the most dramatic transformations was the Parc des Buttes-Chaumont, established on the site of a former quarry, complete with waterfalls and grotto.

[4] Although public parks had previously existed, according to one scholar, "Never before, in Europe or beyond, had landscape architecture played such a prominent role in so vast an urban renewal project.