The fourth son of Sir Harcourt Lees, Bart., he was born on 26 February 1825, and educated at Nut Grove and at Trinity College, Dublin, but took no degree. He was appointed to a Bengal cadetship in 1846, and was posted to the 42nd Regiment of Bengal Native Infantry as ensign in March 1846. He became lieutenant in July 1853, captain in September 1858, major in June 1865, lieutenant-colonel in 1868, colonel in 1876, and major-general in 1885, having been placed on the supernumerary list in 1884.[1]