Born in Victoria, Wells began his career in the Australian Army in 1916 when he entered the Royal Military College, Duntroon. Graduating as a lieutenant three years later, he served in a variety of staff and instructional positions before the outbreak of the Second World War. Initially posted to the 7th Division as a staff officer in 1940, Wells was promoted to lieutenant colonel and made senior liaison officer to I Corps. Serving in Greece and North Africa, he was awarded the Distinguished Service Order for his leadership at El Alamein. Transferred to the South West Pacific theatre in 1943 as a brigadier, he served in the New Guinea Campaign with the headquarters of II Corps and later in the Borneo campaign with I Corps.