E. Parish qualified as Bachelor of Science (BSc) and by 1913 was a lecturer in animal and field husbandry at the School of Agriculture (of the Department of Agriculture) at Elsenburg, near Stellenbosch, where he did some experiments with varieties of grain. In 1920 he was appointed at the Glen College of Agriculture, near Bloemfontein. The next year he was offered an appointment as Director of Agriculture in The Gambia (in West Africa), but he declined the offer. In 1924 he succeeded M.J. Joubert* as head of the college, a position he held until 1926. By 1929 he was principal of the Potchefstroom College of Agriculture. That year he again succeeded Joubert, this time as head of the Grootfontein College of Agriculture (1929-1934). He was a senior official in the Department of Agriculture until 1939 or later.
Parish's publications included Agricultural experiment, it's design and interpretation (Government Printer, 1922); 'The relative economy of ox labour in South African farming' (South African Journal of Science, 1923); 'Problems in agriculture in South Africa', his presidential address before Section C of the South African Association for the Advancement of Science (South African Journal of Science, 1925); a description of the School of Agriculture and Experiment Station at Potchefstroom, Transvaal (Farming in South Africa, 1929); and several papers in the Journal of the Department of Agriculture during the nineteen-twenties. He served as president of the South African Biological Society for 1937 and that same year became a founder member of the Entomological Society of Southern Africa.