Born in 1945, the daughter of a civil servant, Deirdre Purcell was educated at an inner-city primary school and later, as a scholarship pupil, at Gortnor Abbey, a convent boarding-school on Lough Conn. She worked as a civil servant and an Aer Lingus worker; and she joined Aer Lingus Musical and Dramatic Society in 1965. After auditioning for the Abbey Theatre at the behest of a friend, she appeared as Christine opposite Donal McCann in Drama at Inish, Miss Frost in The Ginger Man, Pegeen in The Playboy, and became a permanent member of The Abbey.

After a move to Chicago in 1968, she became actress-in-residence at Loyola, and returned to Ireland in 1973. Finding work in RTÉ, she started as a radio continuity announcer, graduating to the newsroom as a radio newsreader in 1977. She worked as a current-affairs TV journalist from 1979 to 1983, anchoring the Nine O'Clock News.

After joining the NUJ, Purcell became an Irish Press journalist in 1983; Vincent Browne subsequently appointed her chief feature writer for The Sunday Tribune. While there she won the Benson & Hedges and A.T. Cross Journalist of the Year Awards and numerous Jacobs Awards. She was the Taoiseach's nominee to the Board of The Abbey during that period and was appointed as the Council of Credit Institutions Ombudsman. She married in 2001, and now lives in Mornington, Co Meath.

A Place of Stones (TownHouse/Macmillan 1991) was her first novel, the story of Molly Ní Bhriain, an actress from Inisheer. It was an immediate Number One best-seller. That Childhood Country (TownHouse/Macmillan 1992) followed. Falling For a Dancer (TownHouse/Macmillan 1994), in which a pregnant girl from Cork marries a Beara widower to avoid humiliation, was later filmed in West Cork in 1997 and screened in 1998. Purcell wrote the screenplay, which starred Colin Farrell in his first on-screen role. Francey (TownHouse/Macmillan 1994) revisited the story of Elizabeth. Meanwhile Love, Like, Hate, Adore (TownHouse/Macmillan 1997), a sister's defence of her brother charged with rape, was shortlisted for the prestigious Orange Prize. She issued Entertaining Ambrose in 2000. A move from TownHouse led her to Irish publisher New Island, who published her biggest seller ever in original format, the much praised Marble Gardens (2002). New Island also published her ninth novel, Last Summer in Arcadia, in September 2003. Since then she has also written the novels Children of Eve (2005), Tell Me Your Secret (2006), The Secret (2006) and Somewhere in Between (2007), as well as the memoir Diamonds and Holes in My Shoes (2006).

She has also contributed on several occasions to New Island's successful Open Door series.