Mary Lavin was born in East Walpole, Massachusetts in 1912, the only child of Tom and Nora Lavin, an immigrant Irish couple. She attended primary school in East Walpole until the age of ten, when her mother decided to go back to Ireland. Initially, Mary and Nora lived with Nora's family in Athenry in County Galway. Afterwards, they bought a house in Dublin, and Mary's father too came back from America to join them.

Mary attended Loreto College, a convent school in Dublin, before going on to study English and French at University College Dublin (UCD). She taught French at Loreto College for a while. As a postgraduate student, she published her first short story, 'Miss Holland', which appeared in the Dublin Magazine in 1938. Tom Lavin then approached Lord Dunsany, the well-known Irish writer, on behalf of his daughter and asked him to read some of Mary's unpublished work. Suitably impressed, Lord Dunsany became Mary's literary mentor.

In 1943, Mary Lavin published her first book. Tales from Bective Bridge, a volume of ten short stories about life in rural Ireland, was a critical success and went on to win the James Tait Black Memorial Prize for fiction. That same year, Lavin married William Walsh, a Dublin lawyer. Over the next decade, the couple had three daughters and moved to "abbey farm" which they purchased in County Meath which included the land around Bective Abbey. Lavin's literary career flourished; she published several novels and collections of short stories during this period. Her first novel The House in Clewe Street was serialized in the Atlantic Monthly before its publication in book form in 1945.

In 1954, William Walsh died. Lavin, her reputation as a major writer already well-established, was left to confront her responsibilities alone. She raised her three daughters and kept the family farm going at the same time. She also managed to keep her literary career on track, continuing to publish short stories and winning several awards for her work, including the Katherine Mansfield Prize in 1961, Guggenheim Fellowships in 1959 and 1961, and an honorary doctorate from UCD in 1968. Some of her stories written during this period, dealing with the topic of widowhood, are acknowledged to be among her finest.

Lavin remarried in 1969. Michael Scott was an old friend from Mary's student days in University College. He had been a Jesuit priest in Australia, but had obtained release from his vows from Rome and returned to Ireland. The two remained together until Scott's death in 1991.

In 1992, Lavin, by now retired, was elected Saoi by the members of Aosdána for achieving 'singular and sustained distinction' in literature. Aosdána is an affiliation of creative artists in Ireland, and the title of Saoi one of the highest honours in Irish culture.

Mary Lavin died in a Dublin nursing home on 25 March 1996.

Tales from Bective BridgeThe Long AgoThe House at Clewe Street (novel)The Becker WivesAt Sally GapMary O'Grady (novel)A Single LadyThe Patriot SonA Likely StorySelected StoriesThe Great WaveThe Stories of Mary Lavin (Volume 1)In the Middle of the FieldsHappinessThe Second Best Children in the WorldA MemoryThe Stories of Mary Lavin (Volume 2)The Shrine and other storiesA Family Likeness and other stories