Llywelyn Lucas was born in 'Kalimna' (an Aboriginal word for beauty), the home of her mother's family in Gippsland. Educated at schools in Sydney, Melbourne and London, she then studied at a horticultural school in Burnley (Victoria) and became chief gardener on a large property in Melbourne. After the First World War she went overseas, seeing much of Europe and walking through parts of France and Italy. When she returned to Melbourne she worked in a Melbourne garage before moving to Brisbane to work as assistant to her brother, a veterinary surgeon.

Lucas had also planned to become a freelance journalist in Brisbane and her work became well-known to editors and readers. She collected 'Hilarities', humorous newspaper essays by her friend and mentor Hal Eyre (q.v.) and the selection, Hilarities: The Thirty-Nine Indefinite Articles, was published in 1929. Other work included helping Edith England (q.v.) select poems for Queensland Days (1944). Lucas was known as a playwright too and among her plays produced in Brisbane was 'The Sungod's Secret' (a children's play), staged with a large cast of children. According to England, in the Foreword to Lost Kinship and Other Poems (1968), Lucas won several awards for plays.

Lucas went to live at Flinders, in the Fassifern district, where she became interested in astrology. When the Second World War began, she returned to Brisbane and later lived alone for many years at Victoria Point. James Devaney (q.v.), who corresponded regularly with Lucas, wrote that she was 'one of the good minor poets. I think of her as Queensland's first modern; for from the beginning, even before the new influences came sweeping in, she never used the old conventions and diction...' ('The Individual View: Llywelyn Lucas' Meanjin 28.116, 1969, pp.136-137).