Walter Jowett qualified (MRCVS, New Edinburgh) in 1898 and also at some time obtained the Diploma in Veterinary Hygiene. He came to South Africa as a civil veterinarian attached to the British Army Veterinary Department during the Anglo-Boer War (1899-1902). After the war he remained in South Africa and in 1905 was elected a FRCVS for his thesis Tubercular mastitis. From 1906 he served as government veterinary officer in the Veterinary Branch of the Cape Colony. In 1909 he declined an appointment as government veterinary officer in Uganda. After the formation of the Union of South Africa in 1910 he continued as district veterinary surgeon under the new government. His work during these years led to several short papers in the Agricultural Journal of the Cape Colony, dealing, among others, with epizootic pneumo-pericarditis in the turkey (1909), a drug treatment for biliary fever in dogs (canine piroplasmosis) (1909), and fowl spirochetosis at the Cape (1910). During the next few years he continued publishing articles in the Agricultural Journal of the Union of South Africa, on "Actinomycosis" (1911), "Nodular disease of the intestines of cattle" (1911), "Blackhead in turkeys" (1911), "Tuberculosis of food animals" (1913), and "Disinfectants and disinfection" (1913). He also edited and revised the second edition of D. Hutcheon's* Diseases of the horse and their treatment (Cape Town, 1909).
During this period he also contributed many papers to the Journal of Comparative Pathology and Therapeutics, dealing among others with flagellated organisms in the liver of the pigeon (1907), swine plague (1908), the tuberculin test (1909, 1914), cattle trypanosomiasis in Mozambique (1910, 1911), coccidiosis of the fowl and calf (1911), infectious entero-hepatitis in turkeys (1911), and pulmonary mycosis in the ostrich (1913).
In 1911 the British government asked him to join an investigation of the relation between the African fauna and the trypanosome diseases of humans and animals. The next year he was offered an appointment as veterinary pathologist in East Africa, but held out for a bigger salary. When he indicated that he would accept the post in 1913 the vacancy had already been filled. The British government then offered him a post in Zanzibar in 1914, but again he found the salary too low. That year he was appointed superintendent of slaughter houses by the municipality of Cape Town, but the next year resigned from this post in favour of a full-time commission in the South African Defence Force, where he served as officer in charge of the South African Veterinary Corps in the East African Campaign during World War I (1914-1918).
In an article by him in the Agricultural Journal (Union of SA) in 1917 his affiliation is given as the Veterinary Division of the Department of Agriculture in Cape Town. However, he may have transferred to the Royal Army Veterinary Corps at the end of the war. From 1925 or earlier he resided in Edinburgh, where he was associated with the Gorgie Abbatoir. His work there led, among others, to papers on "Two cases of tuberculosis in sheep" (1925) and "Observations on a pyogenic infection of sheep" (1931), both in the Journal of Comparative Pathology and Therapeutics. He bequeethed a sum of money to the University of Cambridge to form the Jowett fund, to be used for the furtherance of research into diseases of animals.