David was born and educated in Glasgow, Scotland where his parents Alexander and Sophia Harper lived. He came to Australia about 1913 ‘to gain colonial experience’ with his cousin David Drummond on his property at Oakwood near Inverell. At the age of twenty one, he enlisted at Inverell and joined with the First Contingent of The Kurrajongs who left Inverell on 12 January 1916 for the Narrabri and Armidale camps.
He became a member of the 33rd Battalion, D Company which after training at Armidale and Rutherford sailed from Australia for England in May on HMAT A74 Marathon. As part of the 3rd Division they trained at Salisbury Plain until sent to France in November 1916. David suffered a gunshot wound to his knee and a leg fracture and subsequently died of wounds on 29 May 1917. He was buried at Trois-Arbres Cemetery, Steenwerck, France.
Private David Harper’s name is inscribed on the Oakwood and Inverell Honor Rolls and the Cenotaph. He was one of the 215 men for whom a memorial tree was planted in Kurrajong Parade in 1919.