Set in a summer villa, Swimming Home is Levy's first novel in a decade.
Traditional publishers turned down the novel and it only hit the bookshelves following the help of supporters and friends and through the use of subscription.
The novel, set on the French Riviera over a single week, examines the devastating effect depression can have on apparently stable people. Judges praised the "technical artistry, glowing prose" and "intimate exposure of loss" in the novel.
Levy, 53, is the author of several novels including Beautiful, Mutants and Swallowing Geography.