In August 1940, Jebb was appointed to the Ministry of Economic Warfare with the temporary rank of Assistant Under-Secretary. He was later appointed chief executive officer of the Special Operations Executive. In February 1942, with a change of Minister of Economic Warfare, Jebb was relieved of that appointment and returned to the Foreign Office. He was appointed Head of the Reconstruction Department and in 1943 was made a Counsellor. In that capacity, he attended numerous international conferences, including those at Tehran, Yalta, Dumbarton Oaks and Potsdam.