John C. Andrew (sometimes Andrews) entered the civil service of the Cape of Good Hope in June 1892. From August 1898 he was a draughtsman in the Engineer's Department of the Cape Government Railways. In January 1900 he was appointed first assistant engineer at Naauwpoort, in the Public Works Department, but in November 1901 was transferred to Port Elizabeth. He returned to the Cape Government Railways as district engineer for the Port Elizabeth - Avontuur line in December 1902. Initially he was stationed in Port Elizabeth, but in 1904 he resided at the Engineers' Camp, Van Staden's (a station just west of Port Elizabeth). In September 1905 he was transferred to De Aar as district engineer. In July 1910, following the formation of the Union of South Africa, he was appointed assistant superintendent (maintenance) of the newly formed South African Railways, a post he held until at least 1914.
Andrew joined the Cape Society of Civil Engineers (established in 1902) during 1903. On 12 July 1905 he read a paper before this society, "Notes on the erection of Van Staaden's Bridge, Port Elizabeth-Avontuur Railway", with A.T. Grant-Dalton* as co-author. The paper was discussed by members on 13 August. Andrew was still a member of the society's successor, the South African Society of Civil Engineers, in 1913.
He was married to Elizabeth H. Probart and during 1894/5 played cricket for the Western Province (one match only).