Marian Keyes was born in Limerick and brought up in Dublin. She graduated with a Law degree at University College Dublin and then 'put it to good use' by going to London and getting a job as a waitress. (According to Under The Duvet, she felt she "did not deserve a better job".) Eventually she was working in an accounts office, when she started writing short stories, with no intention of ever writing a novel (“It would take too long”). She described her career shift as "I became a writer by accident." since she sent her short story manuscripts to a publisher thinking she wouldn't hear back from them, but they did: and asked to see her novel. Thus, Watermelon was written and her career as a novelist was born.
Marian Keyes is a recovering alcoholic, and has incorporated her good and bad life experiences of all types in her books, which are comedies, though the prominent themes and outlined points are dark issues-- including infidelity, inferiority complexes, divorce, drug addiction, bereavement, and domestic violence. In the Walsh family books, the character Rachel Walsh is not based on Marian Keyes, but according to Under The Duvet, her real life experiences in rehabilitation are used in Rachel's Holiday.
Marian lives with her husband, Tony (called "Himself" in her non-fiction works), in Dun Laoghaire after moving back from London in 1997.