John Simpson Kirkpatrick was born in England but later moved to Australia and enlisted in the Australian Imperial Force in August 1914. He served at Gallipoli the following year as Private John Simpson in the 3rd Field Ambulance, Australian Army Medical Corps.

Simpson became famous for his work as a stretcher-bearer and as the man with the donkey at Gallipoli between 25 April, when he landed, and his death in action on 19 May. Using one of the donkeys landed on the first day for water carrying and, later, a second animal he transported wounded men day and night from the fighting in Monash Valley to the beach on ANZAC Cove. He did so, according to CEW Bean, through deadly sniping down the valley and the most furious shrapnel fire. By the time of his death, from machine gun fire as he was bringing down two wounded men, he had saved many lives. He was buried on the beach at Hell Spit.

The War Diary of the 3rd Field Ambulance commended the excellence of the work performed by Pte Simpson continuously since landing. Simpson was posthumously Mentioned in Despatches. His first donkey was known as Abdul, Murphy or Duffy.