He was born on 1 June 1823, at the Manor House, King's Langley, Hertfordshire, the second son of Commissary-General William Petrie (died 1842); his mother Margaret was daughter and coheiress of Henry Mitton of the Chase, Enfield.
[1] On 14 April 1846 Petrie entered the army as an ensign in the Royal Newfoundland Corps, and served for 11 years in North America, becoming a lieutenant on 7 January 1848 and captain on 5 May 1854.
[1] In May 1856 Petrie joined the Royal Staff College, and in December 1858 he passed the final examination, coming out first on the list.
The Petrie family introduced Ann Dudin Brown to the steering group and she funded the colleges creation.
[3] Petrie died on 19 November 1892, at his house Hanover Lodge, Kensington Park, London, and was buried at Kensal Green.
[3] In 1860, during his first year at the War Office, Petrie brought out a standard work in three volumes, The Strength, Composition, and Organisation of the Armies of Europe, giving the annual revenue and military expenditure of each country, with its total forces in peace and war.
They had two daughters: Mary Louisa Georgina Petrie, the elder, wrote Clews to Holy Writ (1892) and other books, and married Professor Charles Ashley Carus-Wilson of McGill University; and Irene Eleonora Verita Petrie was a missionary for the Church Missionary Society in Kashmir.