Clark Maxwell Gray was born on 6 December, 1896 in Dunedin, New Zealand to William Gray and Mary Gray nee Cameron, both born and raised in the Dunedin area. After completing his schooling William Gray worked his way into increasingly senior teaching roles in the Otago region until he undertook a B.A. at the Otago University in 1894, followed by an M.A. 2 years later. He then took on the role as Inspector of Schools in the Wanganui region from 1897 to 1902. In 1895 he married Mary Cameron in Dunedin. The family then moved to Wellington where William Gray took up the position as Principal of the Teacher's Training College in Wellington. Clark's early schooling commenced at the Terrace Primary School, Thornton, Wellington, and then he attended Wellington College from 1909 - 1911. The family then moved to Melbourne where William Gray took on the position of Principal, Presbyterian Ladies College located in Albert Street, East Melbourne at that time. William Gray held this position until 1937. Clark attended Scotch College from 1912 t0 1913. He spent a short time at the University of Melbourne prior to enlisting on 31 May 1914 aged 18 years. Clark had served for 2 years in the Senior Cadets in New Zealand, 2 years in Senior Cadets at Scotch College and under a year with the Melbourne University Rifles, Citizen Military Forces.

Private Gray embarked from Melbourne on board the HMAT A64 Demosthenes on 16 July 1915 and joined the 6th Battalion, 7th Reinforcements at Gallipoli on 5 September, 1915. He was promoted to Temporary Sergeant on 1 October 1915, reverted to Private on 19 November, then promoted twice within a short time, first to Corporal in November, then Lance Sergeant in December 1915. He was part of the general Gallipoli evacuation, disembarking at Alexandria from Lemnos on 7 January, 1916. Whilst in Egypt he was soon promoted to Sergeant on 15 January, 1916, then transferred to the 58th Battalion in February. By March 16, 1916 he was appointed 2nd Lieutenant.

Clark left Egypt for the Western Front on June 11, 1916 embarking from Alexandria on the HMT Transylvania to join the British Expeditionary Force. He disembarked Marseilles 23 June, 1916, transferring to Fromelles. On 16 July, 1916, the AIF was engaged in the Battle of Fromelles, its first on the Western Front. The following day near Fleurbaix, Clarke was killed instantly in No Man's Land sustaining machine gunshots to his arm and stomach whilst delivering ammunitions. Initially there was some thought he had been taken prisoner by the Germans, however several eye witness accounts confirmed he was killed in action. Red Cross records note that  "Lieutenent Kean of 60th Battalion went out and got his pay-book and a small bible out of his pocket". His body could not be retrieved. His death and ultimate sacrifice to his country is commemorated at V.C Corner (Panel No 13), Australian Cemetery Memorial, Fromelles, France. His name is located at panel 165 in the Commemorative Area at the Australia War Memorial, Canberra.