He was previously assistant professor of behavioral science at Cornell University's Johnson Graduate School of Management, assistant professor of marketing at the University British Columbia's Sauder School of Business, and visiting assistant professor at the University of Chicago's Booth School of Business. Leaf is director of the Center for Research on Judgment and Policy; director of the Emotion, Decision, Judgment, and Intuition (EDJI) lab; and an associate editor for the Journal of Personality and Social Psychology. His research examines the interrelation of emotion, judgment, and decision-making in contexts of contemporary significance, including politics, the environment, and well-being. He is an avid cyclist (road and mountain), skier, and hiker. He lives in Boulder, CO, with his wife and their two teenage children.