The catechol-O-methyltransferase (COMT_Val158Met) genetic polymorphism has been linked to variation in affective well-being. Compared with Val carriers, Met carriers experience lower affective well-being. In parallel, research on aging and affective experience finds that younger adults experience poorer affective well-being than older adults. This study examined how COMT and age may interact to shape daily affective experience across the life span. Results suggest that Met (vs. Val) carriers experience lower levels of affective well-being in younger but not in older ages. These findings suggest that age-related improvements in emotional functioning may offset genetic vulnerabilities to negative affective experience.