Environmental sustainability research suffers from a paucity of comprehensive, cross-cultural investigations and lacks insight into the interplay of human values and environmental beliefs and behaviors. In addition, despite the importance of understanding why consumers engage in active attempts to protect the environment, studies looking at the role of environmental sustainability activism remain scarce, poorly integrated, and ill-defined. Against this backdrop, this research captures the links of specific human values with environmental sustainability beliefs and their subsequent relationships with individuals’ environmental sustainability activism and quality of life. Using data from the United States and China, the authors show that religiosity and interdependence are consistently related to environmental sustainability beliefs while, contrary to previous studies, materialism has no significant relationship. In addition, generativity is positively linked with environmental sustainability beliefs only in the U.S. sample, while family values are significant only in the China sample. The results show that environmental sustainability beliefs influence environmental sustainability activities, which in turn are linked with individual perceptions of superior quality of life. The study discusses several implications for practice and identifies fruitful future research directions.