He was the son of John Gerard Buchanan and Annie Elizabeth Buchanan.
In 1901, the family are living in house 27, Main Street, Fintona, Co. Tyrone. John G Buchanan Senior is described as a Bank Manager. There are 3 other siblings; Hugh J Buchanan (aged 5); William Arthur Irvine Buchanan (aged 1) and Margaret J Buchanan (aged 0).
[Hugh J Buchanan joined the Northern Banking Company and also served in the Great War].
[William Arthur Irvine Buchanan served in the Army Veterinary Corps and was killed in action on 24th July 1917].
By 1911, the family property is described as house 23, Main Street, Fintona, Co. Tyrone.
The National Archives records a Medal Index Card as follows:
Royal Field Artillery, 2nd Lieutenant
Family linked to him are Leslie Hastings Buchanan (possibly a cousin) of Ballybolauder, Templedouglas, Co. Donegal, Hugh Johnston Buchanan (brother) and John James Knox Johnston of Crannyvale, Fintona, Co. Tyrone.
He saw service in Kingstown, Saintfield and Aughnacloy. In 1950 he was transferred to Kesh.
The Belfast News Letter of 30th October 1915 reports this of a brother, W A I Buchanan:
The Belfast News Letter of 30th July 1917 reports this of his brother: