Justine Sullivan was born and raised just outside of Baltimore, Maryland, where she failed to learn how to shuck a crab and never attended a single Orioles game. She did, however, discover a passion for reading at her local Harford County Library. She went on to study English Literature at the University of Delaware and then earned her master's in journalism from Boston University and has since spent a number of years working in both newsrooms and the world of branded content.

Justine lives outside of Boston with her family and two terribly behaved dogs. He Said He Would Be Late is her debut novel.