Happiness, generativity and social preferences are pivotal factors for the betterment and sustainability of societies. However, little is known about the relationships among happiness, generativity and social preferences, along with sociodemographic factors, within a single analytical framework. We hypothesize that generativity and social preferences are the determinants of happiness, posing a research question “Are people happier by being prosocial and/or generative for sustainability?” We conduct a survey experiment, collecting data from five subjective happiness scales, generativity, social value orientation and sociodemographic variables in one urban area (Dhaka) and two rural areas (Bogra and Gaibandha) in Bangladesh. With the data, we empirically characterize determinants of subjective happiness with a focus on generativity and social value orientation, controlling for sociodemographic factors. The statistical analysis consistently shows a positive association between subjective happiness and generativity, irrespective of the type of happiness scale, while social value orientation does not exhibit any significance. Rural residents have lower peer relative happiness than urban residents, and household income has a positive relationship with general subjective happiness, leading each of these factors to be significant in overall subjective happiness. In summary, generativity, income and residence area are main determinants of happiness, implying that further urbanization, which is expected to occur in the future, will positively affect people’s happiness if it can bring about an increase in generativity. These results also suggest a possibility that people are happier by being more generative for sustainability, and some new institutional framework such as future design shall be recommended to enhance generativity.