At the end of World War II, he became Minister in charge of the Council for Scientific and Industrial Research and Minister for Postwar Reconstruction in the Chifley government, where he was responsible for promoting full-employment, retraining ex-service personnel and attempting to rebuild the national economy. In particular he had carriage for preparing the White Paper on Full Employment in Australia, establishing the Commonwealth and State Housing Agreement, the Snowy Mountains Scheme, the Joint Coal Board, the Universities Commission and the Australian National University. From November 1946, Dedman was Minister for Defence.