Her acclaimed short-story collection, The End of the World is a Cul de Sac, won the John McGahern Prize. Her debut novel Trespasses has been translated into over twenty languages. A Sunday Times bestseller, it won Eason Novel of the Year at the An Post Irish Book Awards, Book of the Year for Debut Fiction at the British Book Awards and the McKitterick Prize. It was also shortlisted for several awards including the Women's Prize for Fiction, the Waterstones Debut Fiction Prize and the Barnes and Noble Discover Prize. In 2025, Trespasses was made into a limited TV series by Channel 4. Before starting her writing career, Kennedy spent nearly thirty years working as a chef. She lives in Sligo.