

His 2015 book The Ghosts of Heaven, a work of young adult fiction consisting of four loosely connected parts combining in an "intriguing" novel, according to Sarah McCarry. Though a Horn Book reviewer commented that the book could have used further developed characters, the reviewer concluded, "this first novel is sufficiently taut, accessible, and swift moving to make it an effective cautionary tale." In 2013 released Dark Satanic Mills a graphic novel written in conjunction with his brother Julian Sedgwick and illustrated by John Higgins. Floodland tells the story of Zoe, who lives on her own on an island that used to be part of England before global warming caused the sea to rise.

His first book, Floodland, was published in 2000, and it received the Branford-Boase award for the best first children's novel of that year. After working as a bookseller and working in children's publishing, Sedgwick began writing in 1994. Marcus Sedgwick was born in East Kent, England.
