McCaffrey was born in Dublin, Ireland, and teaches Irish history and Irish literature at Johns Hopkins University in Baltimore, Maryland. She is also a frequent lecturer at the Smithsonian Institution in Washington D.C. She founded and edited the literary review Wild About Wilde (1986–96) dedicated to the works of the 19th-century Irish writer, Oscar Wilde.[1] She was the series historical consultant for the three part PBS/RTÉ program In Search of Ancient Ireland (2002) and co-author of the book of the same title.