John Harold Davidson was born at Moonee Ponds, Victoria on 6 July 1895 to parents Francis Lindsay Davidson and Ellen Victoria Davidson (née Tipton). The youngest of four sons, Davidson was educated at Flinders School. From 1910 to 1912, he was a day student at Geelong College. Davidson served for several years as a non-commissioned officer in Senior Cadets and then as a lieutenant for two years. Before the First World War he was employed as a telephone engineer.
Davidson enlisted in the Australian Imperial Force at Geelong on 27 April 1915 and was attached to the 7th Battalion. He embarked from Melbourne with the 7th reinforcements for the 7th Battalion aboard the troopship Demosthenes on 16 July 1915. From that date Davidson was appointed Acting Sergeant.
During the voyage a concert was held on 10 August 1915 in which Davidson sang a song for the sixth item in the program, “I hear you calling me”.
After arriving in Egypt, Davidson was transferred to the Signalling School at Lemnos, Greece, in October 1915. He then joined the 1st Division Signalling Company Engineers on Gallipoli in November 1915 until the evacuation in December. He returned to Egypt in January 1916 and was taken on strength with the 4th Division Signalling Company in March. In April, Davidson was commissioned as second lieutenant and taken on strength with the 5th Pioneer Battalion. He arrived in France during June. In September, Davidson was promoted in the field to lieutenant. From July 1917, he was attached to the Pioneer Training Battalion in England. During March 1918, he was sent to France, where he served in the field until January 1919, when he returned to England to prepare for returning to Australia.
Davidson embarked from England for return to Australia aboard the troopship Kildonian Castle on 21 March 1919. He disembarked in Melbourne on 7 May, and his appointment was terminated on 21 July 1919.
One of Davidson’s brothers, Frank Stanley, who had enlisted in August 1915, was killed at Roisel, France, in September 1918 when an artillery shell exploded in the dugout in which he was sitting. At the time of his death he was a temporary captain in the 2nd Field Company Engineers.
Davidson married Daisy McDonald at Melbourne on 23 July 1920 and the couple had a son, Roy Campbell, born at North Sydney on 6 March 1922.
Following his discharge, Davidson appears to have returned to his former employment as a telephone engineer and his occupation is described as such in the Australian Electoral Roll up to 1949, and then until 1963 as a public servant. Davidson enlisted in the Australian Army on 5 November 1942 and served as a signalman during the Second World War.
John Harold Davidson died at Mt Gambier, South Australia, on 15 January 1971 at the age of 75.