Gullett was born at Toolamba West, Victoria and educated at state schools, but left school at twelve on the death of his father. He began writing for newspapers. In 1908 he travelled to London as a journalist and in 1914 published a handbook on Australian rural life, The Opportunity in Australia to promote emigration to Australia. He married Elizabeth Penelope Frater in 1912 and they had a son and a daughter.
In 1915, Gullett became an official Australian correspondent on the Western Front. In July 1916, he joined the first Australian Imperial Force (AIF) as a gunner. From early 1917 he worked with Charles Bean in collecting war records and later with the AIF as a war correspondent in Palestine. In 1919, he was briefly director of the Australian War Museum. He started writing volume VII of The Official History of Australia in the War of 1914-1918, covering the Sinai and Palestine Campaign, which he completed in 1922. In 1920, Billy Hughes appointed him head of the Australian Immigration Bureau, but he resigned in February 1922 over disagreements in relation to immigration policy and returned to journalism.Click here to hide this biography