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 January 2021, and reached #3 Irish fiction bestsellers list. 'Life Sentences' was published in Czech translation by Paseka, in French by Christian Bourgois, and in the US in April 2022, by David R. Godine as well as on audiobook by Blackstone. Editions are also forthcoming from btb Verlag (Germany) and Petrine Knjige (Croatia).

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, and 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, the Kenyon Review, the London Magazine, Narrative, Ploughshares, Salamander, the Saturday Evening Post and Winter Papers.

A latest novel, The Paper Man, was published in May 2023 by Jonathan Cape (UK) & Godine (USA), and as an audiobook by Blackstone. A translation into Czech is forthcoming, published by Paseka.