Existing happiness research, constrained by the dichotomy between eudaimonia (meaning) and hedonia (pleasure), has failed to achieve an integrated understanding. This theoretical gap cannot adequately explain the ‘paradox of pursuing happiness’—where seeking happiness diminishes it—and has led to a lack of effective communication strategies for enhancing well-being. To address this, the present study hierarchically redefines health as a ‘dynamic adaptive capacity’ to cope with life’s challenges, and happiness as a ‘process of flourishing’ that builds upon that foundation. We then propose the Function-Indicator Model (FIM) as a theoretical framework to explain this process. In this model, the function (eudaimonic happiness) is the process of achieving personal growth toward the purpose of life through the satisfaction of basic psychological needs and self-acceptance. Within this process, adversity is not an obstacle to be avoided but an essential catalyst for growth. In contrast, the indicator (hedonic happiness)—emotions and life satisfaction—signals how well the function is operating. This study posits self-acceptance as the key solution to the happiness paradox, arguing that sustainable happiness lies not in pursuing the indicator (pleasure) but in strengthening the function (meaning) by cultivating self-acceptance as its psychological foundation. Ultimately, by integrating insights from counseling psychology and communication studies, we explore the potential for a new paradigm of salutogenic happiness communication that prioritizes function over indicators.