Content Warning: This section of the guide discusses abuse and infant separation.

Irish writer Claire Keegan was born in 1968 on a farm in County Wicklow, a midland region on the east coast of Ireland where she still lives and where Foster takes place. She is the youngest of her siblings and grew up Roman Catholic like the people in Foster. At age 17, she went to study political science and literature at Loyola University in New Orleans, Louisiana, making her the first person to attend college from her family. She went on to get a Master of Arts at the University of Wales and a Master of Philosophy at Trinity College Dublin. Her first publication, a collection of short stories entitled Antarctica released in 1999, received the Rooney Prize for Irish Literature.

Keegan is renowned for her insight into human behavior, writing often of the same emotions that shape Foster: disconnection, yearning, and surprising compassion. Though recognized much earlier in her native Ireland, Keegan sprang to more widespread prominence when her short novel Small Things Like These (2021) was shortlisted for the 2022 Booker Prize. Like Foster, the book is set in the 1980s in rural Ireland and explores themes of compassion, neglect, and family.