Objective: The tripartite model of depression and anxiety hypothesizes that positive and negative affect is related to depression and anxiety. However, the specific role of cognitive or psychological well-being constructs like resilience and mastery within a tripartite context and throughout adulthood is unclear. Method: Data was drawn from two longitudinal population-based cohorts, aged 20--24 and 40--44 based in Canberra, Australia (N == 3989). We sought to determine the interrelatedness of two affective measures of subjective well-being, positive and negative affect, with two cognitive measures of psychological well-being, resilience and mastery. We then tested their independent effects on depression and anxiety, and hypothesized, following the tripartite model, that subjective well-being would mediate the effects of the psychological well-being variables on mental health and that the psychological well-being variables would be more strongly related to positive subjective well-being. Results: Principal axis factoring delineated four affective and cognitive dimensions of well-being comprising positive and negative affect, resilience and mastery. Structural equation models identified the psychological well-being variables as significantly related to subjective well-being, which fully mediated the effects of resilience and partially mediated the effect of mastery on depression and anxiety. These findings were consistent throughout both young and middle adulthood. Conclusions: Psychological well-being components are significant predictors of subjective well-being affect states that increase vulnerability to depression and anxiety.