 Following his release, Back served on and as a midshipman before volunteering to serve under John Franklin in his first expedition to the Arctic in 1818.Back also served under Franklin in his two overland expeditions to survey the northern coast of North America, first on the Coppermine expedition—when Back was responsible for all the surveying and chart making—and then the Mackenzie River expedition in 1824–1826, during which time he was promoted first to lieutenant and then to commander in 1825.Lacking appointment to a ship, Back was unemployed on the half-pay list, from 1827 to 1833.