John D. McDonald was a writer and editor best known for his work at Fortune magazine in the 1950s and 1960s and as the ghostwriter of the memoirs of Alfred P. Sloan. McDonald was also the first person to popularize game theory. In this article I argue that game theory played a key role in McDonald's transition from documentary writer to business journalist. Game theory gave McDonald a journalistic device to discover business stories and to give those stories a driving tension; he called it a “story engine.” After decades writing with game theory, it began to serve a different purpose for McDonald. By coding business stories as games, McDonald gained insight into the characters, corporate executives who were often brief in explanations and shallow in self-understanding. McDonald's career gives us a glimpse at an extraordinary transformation of how a set of scholarly ideas can become a literary resource for vividness (of stories) and depth (of characters).