<p>A substantial body of research examining the impact of pro-environmental behavior (PEB) on subjective well-being (SWB) has consistently identified a positive relationship between the two variables. However, empirical evidence based on longitudinal data, particularly from non-Western countries, remains scarce. This study investigates the effect of PEB on SWB using Korean panel data from the Survey of Public Attitudes Towards the Environment. While theoretical frameworks suggest that PEB can exert both positive and negative influences on SWB—through mechanisms related to eudaimonic and hedonic well-being—our fixed-effects results reveal that PEB has a marginally significant negative impact on life satisfaction. This negative effect is particularly pronounced for behaviors that involve higher costs. Furthermore, the adverse impact is particularly pronounced for individuals with relatively lower income. We explain these findings by drawing on the data used in the analysis and the cultural context of Korean society, particularly its collectivist orientation and emphasis on material values.</p>