Born into Scottish gentry, John Orrok obtained a commission into the British army while in his early or mid-teens and served in India and Ceylon in the 1790s. On returning to Britain he married his cousin, Betsy Reid, in 1800 and in 1803 they left their baby daughter with Betsy's parents and both sailed to India. John joined first the 65th and then the 33rd Regiment which was led at the time by Arthur Wellesley, later the Duke of Wellington. Although John Orrok reached the rank of captain, he saw very little military action. The couple had three children while in India and after Betsy's death in 1810, Orrok brought them back to England, where he first served as a recruiting officer but then left the army and worked as a bookseller in London. His last known letters came from Brussels in 1816 and less is known of his later life. Orrok moved to Jamaica around 1836 with a second wife, Eliza, and six young children and was employed as the manager of the Jamaica Steam Navigation Company. He and Eliza both died in Jamaica in February 1838.
