In 1925 Hope Simpson was knighted. Following his parliamentary defeat he assumed a number of posts for various organisations, including the League of Nations, as an expert on the question of refugees. He was posted first to Greece to monitor the 1923 population exchange between Greece and Turkey. Following the widespread 1929 Palestine riots he was sent to British Mandate Palestine on a fact finding mission, which resulted in the Hope Simpson Report in 1930. During the 1931 China floods the League of Nations sent Hope Simpson to China, where he became director-general of the National Flood Relief Commission for the government of the Republic of China. As well as coordinating refugee relief, he became a strong critic of the Japanese aerial bombing of a flood refugee camp in Shanghai, following the January 28 Incident. Coming out of retirement at 66 years of age, Sir John became the Commissioner of Natural Resources and Acting-Commissioner of Justice for The Commission of Government of Newfoundland from 1934 until 1936.