Born in Blunham, Bedfordshire. He exhibited landscape views at the Royal Academy, London 1865-88, concentrating on Eastern scenes 1873-7. He was a committee member of the Palestine Exploration Fund and published books on the Holy Land.
He died in London on 3 November 1900 and his obituary described him as of Buckhurst Lodge, Westerham, Kent. Sir Richard Wallace made Harper two payments of 200 guineas in 1873, another in 1874, and one of 10 pounds in 1878.