After both writing and directing his film debut, the 1997 crime thriller Cold Around the Heart, he and Oliver Stone co-adapted Ridley's first novel, Stray Dogs (still unpublished when Stone bought the rights) into the 1997 Stone-directed film U Turn, which was released slightly earlier than Cold Around the Heart. Ridley went on to write the novels Love Is a Racket and Everybody Smokes in Hell. His novel Spoils of War was adapted into the 1999 David O. Russell-directed Three Kings. Ridley's original script was rewritten by Russell and Ridley, with Ridley receiving a "story by" credit negotiated among himself, Russell, and the releasing studio, Warner Bros. Ridley then became a Writer and a supervising Producer on the NBC crime drama Third Watch. His other novels are The Drift, Those Who Walk in Darkness, and A Conversation with the Mann. He also wrote the graphic novel The American Way.