Henry Somer Gullett was born on 26 March 1878 at Toolamba West in Victoria and educated in the Victorian state school system. He left school at the age of 12, after his father's death. In 1900, Gullett joined the staff of the Sydney Morning Herald and was later London correspondent for the Sun and Daily Telegraph (Sydney). 

During World War I, Gullett was appointed by the Commonwealth Government as official Australian correspondent with the British and French Armies on the Western Front (1915); enlisted in the Australian Imperial Force (July 1916); transferred to the Australian War Records Section (1917-18); became Australia's official war correspondent for the AIF in Palestine (1918-19) and was press liaison officer for Prime Minister W M Hughes at the Paris Peace Conference (1919). After his discharge from the AIF, with the rank of Captain, Gullett was appointed by Dr C E W Bean to write Volume 7 of the official war history (1919-22). In this period, he was also the first Director of the Australian War Museum (1919-20), Superintendent of the newly established Commonwealth Immigration Office (1920-22) and, for a time, was on the staff of the Herald (Melbourne).

Gullett was elected to the House of Representatives in 1925 as the Nationalist (from 1931, United Australia Party) member for Henty. He retained the Victorian seat until his death in an air accident at Fairbairn, near Canberra in August 1940.

In the Bruce-Page Coalition Government, Gullett was Minister for Trade and Customs (1928-29). He then became Deputy Leader of the Opposition (1929-30). In the Lyons Government, he again held the Trade and Customs portfolio (1932-33) and was Minister without portfolio responsible for trade treaties (1934-37). In the wartime Menzies Government, Gullett was Minister for External Affairs, Minister for Information and a member of War Cabinet (1939-40) and, later, Vice-President of the Federal Executive Council, Minister in Charge of Scientific and Industrial Research and Minister Assisting in the Information portfolio (1940). He was also a longstanding member of the Australian War Memorial's Board of Management (1926-40).

Sir Henry Gullett was made a Knight Commander in the Order of St Michael and St George (KCMG) in 1933.
 
Publications:

The Opportunity in Australia (London, The Field and Queen, 1914)
(ed with C Barrett) Australia in Palestine (Sydney, Angus and Robertson, 1919)
Official History of Australia in the War of 1914-1918, Volume 7: The Australian Imperial Force in Sinai and Palestine (Syney, Angus and Robertson, 1923)
 
Sources:

Australian Dictionary of Biography, Volume 9 (1891-1939), pp 137-9
McKernan, Michael, Here is their spirit (University of Queensland Press, 1991)
Parliamentary Handbook 1935, p 78; 1968, pp 264, 268, 270, 273-4
Who's Who in Australia 1935, p 214
World War I service dossier: CRS B2455, 'H S Gullett'