Anthony Sillery was born on 19 Apr 1903 in Rangoon (Yangon), Burma (Myanmar). His father was Lt/Col. C.C.A. Sillery, British Officer in the Indian Army.

He was educated at Perse School, Cambridge (1914-1921) and then attended St, John's College, Oxford (1921-1924), leaving with a 1st Class Honour MA and a DPhil.

He served in the British Colonial Service, Tanganyika (Tanzania), from 1925 to 1942, passing exams in Lower Swahili, Higher Swahili, Law (with Honours), and Interpretership in the Kuria Language.

Between 1942 and 1946, he carried out war service in Madagascar (Trade and Finance), and in the Middle East with the British Military Administration, with the rank of Lt/Col., and passed the Army Italian and Arabic examinations. He received the Commander of the Victorian Order as well as British war medals, including the 8th Army clasp.

He was Resident Commissioner for Bechuanaland Protectorate (Botswana) from 1947 to 1951 and from 1951 he was Secretary to Curators of Taylor Institution, Oxford, and teacher of Colonial Government and African Languages in the Devonshire Course under the Institute of Commonwealth Studies. He was a Tutor and Lecturer of the Bechuanaland Foreign Service Course in 1966 as well as a Research Student in the School of Modern History and a Fellow of the Royal Historical Society.

He belonged to the Society of Authors and the Ski Club of Great Britain, and enjoyed walking and trout fishing.