One of five children of woolbroker Alfred Stanley Cheadle and his wife Margaret (Loutit), Frances Margaret McGuire grew up in Glenelg and at Mt Lofty, as recalled in her book Bright Morning. She studied science at the University of Adelaide, the only woman among 100 science students. She became a biochemist and was involved in research on insulin.
In 1927 McGuire married Paul McGuire (q.v.), who was at the time special overseas correspondent for various newspapers and they subsequently lived in Europe, Asia and the USA. She represented Australia at the League of Nations in 1939. Paul McGuire served in the RAN Volunteer Reserve during WW II and in 1953 he was appointed Australia's first ambassador to Italy.
Mcguire wrote for newspapers, and published books on the Royal Australian Navy, The Price of Admiralty (1944) and The Royal Australian Navy: its origin, development and organisation (1948). She translated The Flight of the Falcon by John Gerard (1954) and wrote (with Paul McGuire and B. Arnott) The Australian Theatre: an abstract and brief chronicle in twelve parts (1948). Her other non-fiction includes Gardens of Italy (1964). She co-edited the literary quarterly, Orion (1919-1921), and was co-founder of the Dante Alighieri Society of South Australia, winning cultural awards from the Italian government. McGuire was on the National Council of Women and chaired the Women's Memorial Trust. Her personal papers, held at the State Library of South Australia, contain an unpublished manuscript, Remembering my Father (1943-1944) and Letters from Manfred, by Manfredo Pedicini-Whitaker, which she edited.
Paul McGuire, also a writer, died in 1978. He had always been passionately interested in the sea, so, beginning with his extensive collection of books, McGuire founded in 1978 the Paul McGuire Maritime Library in the State Library of South Australia. She said it had been through her husband that she had started writing books. He had signed a publisher's contract to write a particular book but was unable to fulfill it because of the war, and she was asked if she would write it instead. She did, and she enjoyed the experience and continued to write.
In 1994, at the age of 94, McGuire published Victory for Yarra. She then moved house in order to write another book, but died in 1995 before achieving her aim. She was awarded the Order of Australia in 1995 for services to the sea and to literature.