Louise O'Neill grew up in Clonakilty, a small town in West Cork, Ireland. Her first novel, Only Ever Yours, was released in 2014 and won the Sunday Independent Newcomer of the Year at the Irish Book Awards, the Eilís Dillon Award for a First Book and the Bookseller's inaugural YA Book Prize. Her second novel, Asking For It, was published in September 2015 to widespread critical acclaim. It spent 52 consecutive weeks in the Irish top 10 bestseller list. Both novels have been optioned for screen.

Louise's first novel for adults, Almost Love, was published in 2018, followed shortly by The Surface Breaks, her feminist re-imagining of The Little Mermaid. Her second novel for adults, After the Silence, was published in 2020 and was an instant bestseller in Ireland. It won Crime Novel of the Year at the Irish Book Awards and has also been optioned for screen. Idol is her third adult novel.

Louise contributes regularly to Irish TV and radio, and has a weekly column in the Irish Sunday Times.