In 1960 he became minister of agriculture. The moving force behind theAgricultural Rehabilitation and Development Agency, he engineered several wheatsales to China that gave a much needed boost to Western agriculture. Defeatedin 1968 he was re-elected in 1972 and held the seat until retiring frompolitics prior to the 1988 general election. Hamilton entered the Order ofCanada in 1987 as a Companion and was bestowed the title Right Honourable in1992 by the Queen in honour of his service to Canada.