After the war he returned to the Service, spending three years in Ashanti and two in Ghana before being posted in 1958 to the West PacificHigh Commission as Chief Secretary.
From then until his retirement in 1973 he remained in the Far East, notably in Hong Kong where he was Colonial Secretary and Acting Governor intermittently between 1965 and 1969. In the colonial secretary's tenure, he and Ronald Holmes and Jack Cater and other government officials had to deal with riots in 1967 against British colonial rule. During the disorder, GovernorSir David Trench happened to be absent from Hong Kong and all of a sudden there was no one fully in command of the government. As a result, Gass became acting-Governor, and therefore it was Holmes and Gass who were in charge in the crisis. During the riots, he took a tough stance against the activists, to effectively control the situation, but has also become one of the main targets of attack leftist camp vocal opposition.
^ abc"Gass, Sir Michael David Irving". Gass, Sir Michael David Irving, (24 April 1916–27 Feb. 1983), HM Overseas Civil Service, retired. Who's Who. 2007. doi:10.1093/ww/9780199540884.013.U164451.