Born in St. John's, Newfoundland and Labrador, Moore studied art at the Nova Scotia College of Art and Design. Although she had intended to follow a career in the visual arts, she now writes full time.
Her 2002 book Open was a commercial and critical breakthrough, earning a nomination for the Giller Prize. Her first novel, Alligator (2005), was also nominated for the Giller Prize. It won the 2006 Commonwealth Writers' Prize Best Book Award, Caribbean and Canada Region, and is longlisted for the 2007 IMPAC Award. Moore often incorporates her Newfoundland heritage in her work; Alligator, for example, is set in St. John's.