James Devaney was born in Bendigo, Victoria, and was educated at St Joseph's College in Sydney. He became a Marist brother and took the religious name Brother Fabian, which he used as an early pen-name. As a Marist brother, he served as a teacher and tutor in North Queensland, and it was here that his lifelong interest in Aboriginal lore began. In 1929 he published The Vanished Tribes, a collection of stories from Aboriginal mythology.
Devaney's first book of poetry was Fabian (1923), and later books of verse included Dark Road (1939), which was addressed to his ill wife; and Earth Kindred (1931) and Where the Wind Goes (1939), which celebrated the beauty of nature. In 1950 Devaney produced the self-selected collection, entitled Poems (1950). A keen observer of nature, Devaney also contributed nature columns to several periodicals. He wrote many essays of literary criticism, and he criticised modernist poetry in Poetry in Our Time (1952).
Devaney was a friend and biographer of John Shaw Neilson, and he encouraged many younger writers, including the Aboriginal poet Oodgeroo Noonuccal. His final works included a dramatised account of the life of Christ entitled The New Law (1955), and the small book of verse, Towards Evening (1974). Devaney died in Brisbane in 1976 at the age of 86.
A number of plays by Devaney are held in manuscript form in the James Devaney Papers, John Oxley Library, Brisbane. Composition dates and any production details are still being confirmed for some works.