The ways in which we travel—by what mode, for how long, and for what purpose—can affect our sense of happiness and well-being. This paper assesses the relationships between measures of the sustainability of transportation systems in U.S. metropolitan areas and subjective well-being. Associations between self-reported happiness levels from the Gallup Healthways Well-being Index and commute data were examined for 187 core-based statistical areas (CBSA). We also supplement this quantitative analysis through brief case studies of high- and low-performing happiness cities. Our quantitative results indicate that regions with higher commute mode shares by non-automobile modes generally had higher well-being scores, even when controlling for important economic predictors of happiness. We also find that pro-sustainable transportation policies can have implications for population-wide happiness and well-being. Our case studies indicate that both high and low scoring happiness cities demonstrate a dedicated commitment to improving sustainable transportation infrastructure. Our study suggests that cities that provide incentives for residents to use more sustainable commute modes may offer greater opportunity for happiness than those that do not.