Wellesley was educated at Trinity College, Dublin, graduating B.A., M.B., B.Ch and B.A.O. in 1909. He took up the posts of house-surgeon at Monkstown Hospital, Dublin; and of second assistant medical officer at Nottingham City Asylum, before coming junior assistant medical officer at Broadmoor Criminal Lunatic Asylum, Berkshire. On 5th July 1915, he took up a temporary commission as lieutenant in the R.A.M.C., then entered the war in Gallipoli on the 30th September. He was promoted to Captain after one year’s service. Wellesley died of typhus at Cairo. He was the son of Dr W Hamilton and Margaret Allen of Stanmore, Middlesex.