Born 20 February 1991, is an Irish author and screenwriter. Rooney was born in Castlebar, County Mayo, in 1991, where she also grew up and lives today, after studying in Dublin and a stint in New York City. Her father, Kieran Rooney, worked for Telecom Éireann and her mother, Marie Farrell, ran an arts centre. Rooney has an older brother and a younger sister. She studied English at Trinity College Dublin (TCD), where she was elected a scholar in 2011. She started (but did not complete) a master's degree in politics there, completing a degree in American literature instead, and graduated with an MA in 2013.

While attending Trinity College Dublin, Rooney was a university debater and eventually became the top debater at the European Universities Debating Championships in 2013, later writing of the experience. Before becoming a writer, she worked for a restaurant in an administrative role.

She has published three novels: Conversations with Friends (2017), Normal People (2018), and Beautiful World, Where Are You (2021). The first two were adapted into the television miniseries Normal People (2020) and Conversations with Friends (2022).