Is it possible to enhance the subjective wellbeing of individuals and societies? If so, what are the mental health interventions and economic mechanisms by which subjective wellbeing could be enhanced? We address these questions in our review of the literature on subjective wellbeing. Research now shows that although subjective wellbeing is heritable and stable, it can change substantially over time. Long-term changes can be affected by positive or negative life events; subjective wellbeing interventions have also proved to be effective for boosting wellbeing for as long as six months. At the societal level, economic factors matter for the subjective wellbeing of citizens. Economic wealth is shown to be a predictor of societal wellbeing across countries and over time. Also, high unemployment severely lowers the wellbeing of individuals and has spillover effects on other societal members, such as the employed. Given the weight of evidence, we are optimistic that subjective wellbeing can be enhanced. For practitioners, policy makers, and economists interested in the wellbeing of individuals, we propose that these findings have implications for mental health practice and economic policies. Future research and methodological issues are discussed.