Verny was sent to Ningbo and Shanghai in China from 1862 to 1864,[3] to supervise the construction of four gunboats for the Chinese Navy, as well as a new shipyard.

Verny was persuaded to go to Japan by his distant relative, French ambassador Léon Roches in September 1865, who negotiated the substantial annual salary of $10,000.

The same year, he briefly returned to France to purchase all necessary machinery and recruit French naval experts from Brest, Toulon, and Cherbourg (45 families in all) to help organize the construction of the arsenal.

During the months in France, Verny also helped in the negotiations for the first French military mission to Japan, consisting of military advisors under Jules Brunet to help train and re-equip the Tokugawa army from 1867, and to assist it in the Boshin War against the Satchō Alliance.

The construction of the shipyard itself was only the central point of a major infrastructure development project, which encompassed foundries, brick kilns, gunpowder and weapons factories, an aqueduct and hydraulic power facilities, modern buildings and technical schools to train Japanese technicians were established.

Yokosuka became one of the main arsenals of the Imperial Japanese Navy into the 20th century, in which were built battleships such as Yamashiro, and aircraft carriers such as Hiryū and Shōkaku.

The dry docks built by Verny are still intact and are currently used by the US Navy as part of the United States Fleet Activities Yokosuka.