Sir Robert Thorne Coryndon, CMG (Companion of the Order of St Michael and St George) (1911), KCMG (Knight Commander of the Order of St Michael and St George) (1919), was born in South Africa on 2 Apr 1870. He was educated in South Africa at St. Andrew's College, Grahamstown, and in England at Cheltenham College.

It was intended that Coryndon should follow his father's profession of the law, and, with that object, he returned to South Africa in 1889, at the age of 19, in order to serve his articles with his uncle's firm, Caldecott and Bell of Kimberley. However, in the same year, Coryndon left office-work and joined the Bechuanaland Border Police under the British South Africa Company. In the following year, he became a member of the Pioneer Force occupying Mashonaland (Zimbabwe). He served in campaigns in Matabeleland in 1893 and 1896, and formed part of the band of young South Africans known as Rhodes' 'Lambs' or 'Apostles'.

In 1896, Coryndon became Private Secretary to Cecil Rhodes; he acted in that capacity during the Parliamentary Inquiry into the Jameson Raid (1896). However, although he always supported Rhodes' ideals, he did not care for the position and, in the following summer, Rhodes sent him to represent the British South Africa Company in Barotseland. Shortly afterwards, Coryndon took over the administration of North-Western Rhodesia (Zambia), in collaboration with the Barotse chief, Lewanika, and remained there until 1907. Coryndon was then transferred to Swaziland (Eswatini) where, as Resident Commissioner, he was chairman of the Southern Rhodesian Native Reserves Commission of 1914-1915.

In 1916, Coryndon was appointed Resident Commissioner in Basutoland (Lesotho) and a year later was appointed Governor and Commander-in-Chief of Uganda; he assumed the government in 1918. He was appointed to his final post in 1922 as Governor and Commander-in-Chief of Kenya and High Commissioner of Zanzibar. The Duke and Duchess of York visited East Africa over Christmas 1924. In Jan, they left for Uganda and Lady Coryndon embarked for England, where Coryndon was shortly to join her and their four children. However, on 10 Feb 1925, Sir Coryndon died in Nairobi after an emergency operation. Edward Denham acted as Governor until Sir Edward Grigg's arrival later in the year.