 On January 1, 1862, Hanks joined Company H of the 12th Connecticut Volunteers.In mid-1862, the 12th Connecticut moved to the area around New Orleans, and Hanks was stationed in the garrison of Camp Parapet, about 10 miles north of the city.In late-September 1862, Hanks was detailed as Aide de Camp of Brigadier General Thomas W. Sherman for the superintendence of contrabands, slaves who had escaped and joined Union lines.