Hector Roy McLarty was born on 3 March 1887 to Hector Neil McLarty and Elizabeth McLarty (née Campbell) in Fremantle, Western Australia, one of six children. His grandparents, John and Mary Anne McLarty, were among the first pioneers in Western Australia. They had arrived in April 1838 and established the property Blythewood, near Pinjarra, which served as an inn, pub and post office as well as the family home.

On 1 January 1903, Hector Roy McLarty began work at the Australian Mutual Provident Society (AMP), where he remained until his retirement on 2 March 1950, apart from his military service.

McLarty enlisted in the Australian Imperial Force on 27 August 1914, and was appointed to the 8th Battery, 3rd Field Artillery Brigade. He embarked from Fremantle on 31 October 1914, on HMAT Medic. His youngest brother, Duncan Keith McLarty, served as a piper with the 9th Black Watch, and was killed on 25 September 1915 during the Battle of Loos. Hector McLarty arrived on Gallipoli during the landing, and remained until the evacuation on 20 December 1915. His unit was sent to the Western Front, and McLarty received a gunshot wound to the thigh on 10 June 1917 during the battle of Messines, and was sent to England for treatment. He was awarded the Military Medal on 16 August 1917 for his actions and bravery in the field at Messines. He rejoined his unit in France in October 1917.

On 27 December 1918, he married Matilda Mary Stanton, at St Mary Magdalene Church in Wandsworth, London. The couple returned to Western Australia in early 1919. McLarty resumed his work at AMP and the couple lived in Perth, Adelaide and Melbourne. Hector Roy McLarty died on 10 September 1964 at Box Hill Hospital, aged 77.