© The Author(s) 2019.Perceived partner responsiveness (PPR)—the extent to which people feel understood, cared for, and appreciated—has been identified as an organizing principle in the study of close relationships. Previous work indicates that PPR may benefit physical health and well-being, but how PPR is associated with personal benefits is less clear. One cognitive mechanism that may help to explain these associations is perceived control. Here we tested two competing models (moderation vs. mediation) in which we assessed whether perceived control might explain how PPR impacts health, well-being, and mortality in a 20-year longitudinal study of adults (N = 1,186). We found that PPR has a long-term positive association with health, well-being, and mortality via increased perceived control and, in turn, decreased negative affect reactivity to daily stressors. These findings have important implications for understanding the cognitive mechanisms that link PPR to health and well-being.