Rea joined the colonial administrative service in 1931, and went to British Malaya where he served in various posts including: officer in the
Chinese Protectorate,
Federation of Malaya (1948); Deputy Commissioner for Labour, Federation of Malaya (1949), and Deputy Malayan Establishment Officer (1950). In 1952, Rea transferred from the Malayan government establishment to
Singapore where he held the appointment of Deputy President of Singapore City Council. In 1953, he was appointed a member of the
Legislative Council, and in 1955 was appointed to the substantive position of President of Singapore City Council. Intending to retire in June 1957, he agreed to a six months extension to oversee constitutional changes. During the following year, Rea was appointed Chief Administrative Officer but after the
1958 Singapore City Council by-election, the
People's Action Party led by
Ong Eng Guan which controlled the council objected to his appointment because Rea was a member of the Malayan Civil Service and a government official. The last president of Singapore City Council, Rea retired in 1958. After leaving Malaya, Rea returned to Ireland and joined the
Northern Ireland Civil Service, serving in various posts including: chairman of the Hotel Grants Advisory Committee, Northern Ireland (1963–1975); member of the
Headmasters' and Headmistresses' Conference (1966–1973) and as chairman (1971–1973); Eastern Health and Social Services Board (1974–1978);
Northern Ireland Housing Trust (1959–1971) and as vice chairman (1970-71); Tailoring Wages Council, (1965–1982), and
General Dental Council (1961–1979). == Personal life and death ==