[1] In 1931, Barrett joined the Malay civil service as a cadet, beginning his career as secretary to the British Adviser, Kedah.
[2][3] For the next eleven years, he served in many posts in Malaya and Borneo.
[1][4] In 1949, he was appointed Chief Registration Officer, Federation of Malaya,[5] in 1951 he was President of the Municipal Council of Kuala Lumpur,[6] and the following year he was appointed Commissioner for Resettlement of Special Constables in Civilian Life, Federation of Malaya.
[1][4][7] In 1953, he was appointed Acting British Adviser, Perak and a member of the Perak State Council,[8] but was transferred later the same year to the post of British Adviser, Kedah, remaining in the position until 1957 when the post was abolished.
[1][4] Barrett married Eleanor Nelson Raymond in 1936, and they had one son.