Francis Patric Fleming (later spelled Flemyng) served three years as an ensign in the 81st Regiment of Foot before entering Magdalen College, Cambridge, where he qualified as Bachelor of Arts (BA, 1847) and Master of Arts (MA, 1852). He was ordained in the Anglican Church in 1847, and became a priest in 1852. From 1849 to 1853 he served at King William's Town, Cape Colony, as chaplain to the troops. During this period he helped to found the earliest mission in the Eastern Cape, and started construction of the Holy Trinity Church. His experiences and observations in South Africa were described in two books and a journal article. In Kaffraria and its inhabitants (London, 1853, 144p) he described the region in which he had served, including some information on its climate, fauna and flora, and illustrated it with his own pencil sketches. This was followed three years later by Southern Africa: A geography and natural history of the country, colonies, and inhabitants from the Cape of Good Hope to Angola (London, 1856, 487p). The latter was a useful compilation of information about the region and its native inhabitants, and was written as a guide book for missionaries, military officers, emigrants and travellers. His paper, "A short account of a journey across the rivers of British Kaffraria, thence from the Great Kei to the Gnabaka River [not identified], with a description and sketches of fossil remains near the mouth of the Gnabaka", was published in the Proceedings of the Royal Geographical Society (1856, Vol. 1, pp. 511-512). He was a competent artist and some of his water colours are in the East London Museum. Reproductions of the 33 wood engravings with which his two books were illustrated are included in the Catalogue of prints of the Africana Museum, Johannesburg.
Upon leaving South Africa Fleming served for four years as chaplin to the forces on Mauritius and published a book, Mauritius, or, the Isle of France..., in 1862. During the eighteen-sixties he was the chaplain of Princess Alice at Hesse-Darmstadt. He served as hospital chaplain during the Franco-Prussian War and during the eighteen-seventies held various posts in Scotland. From 1885 to 1887 he was chaplain to the Anglican community of Pau, in southern France.