Leon Gellert was born and educated in Adelaide. He was a school teacher before enlisting as a private in the 10th Battalion AIF. He took part in the Gallipoli landings, where he was wounded and sent to England to recuperate, before returning to Australia in 1916.
In 1917 Gellert published Songs of a Campaign which won the University of Adelaide's Bundey prize for poetry, establishing him as a foremost Australian war poet. His work reflected a realism about war not seen in the more conventional 'heroic' war verse. A friend of Sydney Ure Smith and Norman Lindsay, he moved from teaching into journalism, editing Art in Australia from 1922-1938, and Home magazine. He co-edited with Sydney Ure Smith several books of Australian art, including work by Margaret Preston, Hans Heysen and Norman Lindsay. He later became literary editor, columnist and book reviewer with the Sydney Morning Herald and the Daily Telegraph.
His many publications include the long allegorical poem The Isle of San (1919), Desperate Measures (1928), a book of light verses on native animals, Those Beastly Australians (1944), and collections of his journalistic articles, Week after Week (1953) and Year after Year (1956).