Coles, a Brit, has held the editorial position in the US since 2012, and is replaced by executive editor Michele Promaulayko.
Coles has been handed an international remit in her new role, which entails identifying new ways for Hearst to expand beyond magazines and digital properties into TV and live events.
President David Carey told The New York Times that companies wanting to work with Hearst often approached through Coles. She sits on Snapchat's board, and Cosmopolitan is the only Hearst property that features on the app's Discovery channel, which pushes its users to publishers.
Coles told The New York Times: "I love Cosmo, but I gave it everything I had. I just didn’t have another sex position in me."