The article proposes a functional approach as a framework for the analysis of human well-being. The model posits that the adaptive role of hedonic feelings is to regulate stability and homeostasis in human systems, and that these feelings basically are created in states of equilibrium or assimilation. To regulate change and growth, a distinct set of feelings exists, which may be labeled eudaimonic feelings. Eudaimonic feelings are produced to motivate behavior in challenging environments, when a quick return to equilibrium is dysfunctional, or when accommodation of cognitive structures is needed for a stimulus or event to be perceived as meaningful. It was hypothesized that a trait-like concern for evaluation of outcomes in terms of goodness or badness, referred to as hedonic orientation, will moderate the relation between equilibrium/assimilation and hedonic feelings. The model also includes the concept of eudaimonic orientation, reflecting a stable tendency to get involved in challenging activities and to create and strive after demanding goals. It was hypothesized that a eudaimonic, and not a hedonic, orientation moderates hedonic feelings in challenging episodes. Three different studies gave empirical support to the model.