Curtayne is the youngest child of John Curtayne, founder and proprietor of the Tralee Carriage Works, and his wife Bridget Curtayne (née O’Dwyer). She receives her initial education at local convents before attending La Sainte Union College in Southampton, England. Having taken a typing course, she is engaged as a secretary in Milan, where she remains for four and a half years. This proves to be a formative period in her life. She comes to regard Italy as a second home and is greatly influenced by the work of the Italian Catholic philosopher, Giovanni Papini.
On leaving Italy Curtayne works for a time in Liverpool. She joins the Liverpool Catholic Evidence Guild, from where she receives her diploma as a diocesan catechist. While in England she also develops an interest in public speaking. Her first book, Catherine of Siena (1929), is followed by numerous publications on religious and historical subjects, including Lough Derg (1933), Patrick Sarsfield (1934), The Trial of Oliver Plunkett (1953), Twenty Tales of Irish Saints for children (1955), and The Irish Story (1962).
Curtayne’s enthusiasm for Italy is reflected in her many publications of Italian interest, including a scholarly work on Dante, and a novel House of Cards (1940), which centres on the experiences of a young Irish woman living in Italy. In 1972 she produces Francis Ledwidge: A Life of the Poet, her well regarded biography of the poet Francis Ledwidge, and in 1974 it is followed by an edition of his complete poems, The Complete Works of Francis Ledwidge. Throughout her journalistic career she is a contributor to various magazines and papers, among them The Irish Times, Irish Independent, The Irish Press, Books on Trial, The Spectator, and The Standard.
During the 1950s and early 1960s Curtayne makes five lecture tours in the United States, speaking on Irish life, history, and literature. In 1959 she receives an honorary doctorate in Humane Letters from Anna Maria College in Paxton, Massachusetts, where she briefly teaches. She is presented with the Key to Worcester City by Mayor James D. O’Brien. She also gives a course of lectures on Dante at Craiglockhart College, Edinburgh, in 1956, and in 1965 she again speaks on Dante in a Radio Éireann Thomas Davis lecture.
In December 1954 The Irish Press sends Curtayne to Rome to write daily reports on the close of the Marian year. She goes to Rome again for the final session of the Second Vatican Council. She is commissioned to send weekly reports to local newspapers, The Nationalist (Carlow) and The Kerryman. She also sends a series of profiles of outstanding personages of this Vatican Council to The Universe and an article for Hibernia journal.
In 1935, Curtayne marries the English-born writer and broadcaster Stephen Rynne, with whom she has two sons and two daughters. They run a farm at Prosperous, County Kildare, and are well known advocates of the values of rural living. One son, Andrew Rynne, becomes a medical practitioner and well known for his liberal views on birth control. Daughter Brigid Rynne later illustrates some of her mother’s books.
Curtayne dies on August 9, 1981, in the Hazel Hall Nursing Home in Clane, County Kildare, and is buried at Killybegs Cemetery.