The Commonwealth War Graves Commission states that Lieutenant Hay was the son of John and Mary Ann Hay of Glendon Street, Maori Hill, Dunedin and born at Invercargill. In fact John's father, John Hay had died in Invercargill on 1 August 1907.

He was engaged to be married to Sheila MacDonald MacLean of Queen Street, Dunedin. She later married Herbert Glendining and died at the time of the birth of her only child. AWMM