Henry Lesley was born in Dumfries on 12 December 1889, the son of Henry Wyvil Lesley and Annette Eleanor Lesley (née Harrison). He joined the Royal Navy as a Cadet on 15 September 1904. He was promoted to Midshipman on 15 January 1906, and was appointed to the cruiser HMS LEVIATHAN on the same date. On 27 November 1906 he joined the cruiser HMS BACCHANTE and then was appointed to the battleship HMS HINDUSTAN on 17 September 1907. Promotion to Sub Lieutenant followed on 15 March 1909 and he was then appointed to the battleship HMS AGAMEMNON and promoted to Lieutenant on 15 June 1910. On 1 August 1914, he was appointed to the battleship HMS CANOPUS and at the time of the Battle of the Falkland Islands, HMS CANOPUS was in Stanley Harbour and Henry Lesley was ‘Commended by the CO CANOPUS for services in connection with Defences of Stanley Harbour, Falklands Islands.’

He was appointed to HMS DOLPHIN 1 March 1917 as Signals Officer on the Staff of Commodore (S). On 16 September 1917 he was at sea in HMS G9.  G9 was on patrol in the North Sea and fired a torpedo at the destroyer HMS PASLEY believing the Destroyer to be German. The torpedo did not explode, and HMS PASLEY rammed G9 which sank. There was only one survivor, but it was not Henry Lesley.

At that time the Lesley family were living at Aldeburgh in Suffolk. He is commemorated on the Portsmouth Naval War Memorial on Panel No. 26 and on the Aldeburgh town war memorial.