Oisín McGann was born and raised in Dublin and Drogheda, County Louth, in Ireland. He studied art at Senior College Ballyfermot and Dún Laoghaire School of Art, Design & Technology. Before becoming an author, he worked as a freelance illustrator, serving time along the way as a pizza chef and a security guard, as well as a background artist for an animation company and an art director and copywriter in an advertising agency.