Roger Lancelyn Green was born on November 2, 1918, the son of a Royal Air Force officer. He was educated in private schools in Surrey, England, and graduated from Merton College, Oxford, with a bachelor of literature degree. At Oxford he was a part-time professional actor and a department librarian. He went on to teach at the University of Liverpool and the University of St. Andrews in Scotland.
Green is a poet as well as the author of books on folklore, and has written a biography of the great storyteller Andrew Lang (Andrew Lang: A Critical Biography, 1946). He was editor of the Kipling Journal and the author of Kipling and the Children (1965). His interest in Lewis Carroll led him to edit the Diaries of Lewis Carroll (1953) and The Lewis Carroll Handbook (1962).
Green authored two books about C. S. Lewis—a critical work published in 1963 and a biography in 1974. He has also written about J. M. Barrie, the author of Peter Pan; Mary Louisa Molesworth, an author of children's books; and A. E. W. Mason, who wrote historical romances and mystery novels. Green is an accomplished storyteller whose interest in myth and legend has inspired over thirty books of tales from ancient Greece, ancient Egypt, and Israel, and from the Norse and Arthurian legends.