Billy O'Callaghan was born in Cork, Ireland, in 1974. His books include the short story collections: In Exile (2008, Mercier Press), In Too Deep (2008, Mercier Press), and The Things We Lose, the Things We Leave Behind (2013, New Island Books/2017, CITIC Press, China); and a novel: The Dead House (2017, O'Brien Press/Arcade, USA).

His breakthrough novel, My Coney Island Baby, was published in 2019 by Jonathan Cape (UK, Ireland & the Commonwealth) and Harper (USA), as well as in translation by Grasset (France), Ambo Anthos (the Netherlands), btb Verlag (Germany), Paseka (Czech Republic), Ediciones Salamandra (Spain), L’Altra Editorial (Catalonia), Jelenkor (Hungary), Guanda (Italy) and Othello (Turkey). The novel was also shortlisted for the Royal Society of Literature's Encore Award.

A new short story collection, The Boatman, and Other Stories was published in 2020 by Jonathan Cape (UK) and Harper Perennial (USA), and is forthcoming from btb Verlag (Germany) and Sefsafa (Egypt - Arabic).

His novel, Life Sentences, published to critical acclaim by Jonathan Cape in 2021, and reached #3 Irish fiction bestsellers list. 'Life Sentences' was published in the US by David R. Godine as well as on audiobook by Blackstone, as well as in Czech translation by Paseka, in Croatian by Petrine Knjige, in Farsi by Rahetalaei, and in French by Christian Bourgois. The French edition was shortlisted for the Prix Littéraire UIAD and the Littératures Européennes Cognac Prix du Lecteurs. An edition of the book is also forthcoming from btb Verlag (Germany) in April 2025).

His work has been recognised with numerous honours, including Bursary Awards for Literature from the Arts Council of Ireland and the Cork County Council, a Bord Gais Energy Irish Book Award, as well as being shortlisted for Encore Award and Costa Short Story Award shortlistings, and his short stories have appeared in more than 100 magazines and literary journals around the world, including: Agni, the Bellevue Literary Review, the Chattahoochee Review, Fiction Magazine, the Kenyon Review, the London Magazine, the Massachusetts Review, Narrative, Ploughshares, Salamander, the Saturday Evening Post, the Stinging Fly and Winter Papers.

His latest novel, The Paper Man, was published in May 2023 by Jonathan Cape (UK) & Godine (USA), and as an audiobook by Blackstone. It has also been translated into Czech, published by Paseka.