He commanded the 3rd Infantry Brigade, part of Major-General Sir Harold Alexander's 1st Infantry Division, from 1938 to 1939. Handing over the brigade to Brigadier Thomas Wilson, a fellow KRRC officer, he was sent home from France in December 1939 and promoted to acting major-general on 21 December (with seniority backdated to 18 July 1938), to assume command of the 46th Division. Curtis rejoined the British Expeditionary Force (BEF) with his division in April 1940. Evacuated from Dunkirk, he was appointed to command the 49th (West Riding) Infantry Division in June 1940 which, at a reduced establishment, was detailed to occupy Iceland. Curtis spent the next two years in charge of his division from his office in Reykjavik. Made commander of Salisbury Plain District 1943, he was appointed commander of the Hampshire District in 1944 and the Dorset District in 1945. He retired from the army in 1946.