Emerging adulthood represents a critical phase for the development of purpose in life, yet little is known about the process through which young people become purposeful, or what the lasting benefits of such purposefulness might be. The present investigation explored four primary hypotheses though three interconnected studies. The first hypothesis, addressed in Study 1 using cross-sectional data, posited that purpose and meaningful engagement would be associated with psychological well-being. The second hypothesis proposed a mediational model, wherein the relationship between meaningful engagement and psychological well-being would be mediated by purpose; this hypothesis was tested first with cross-sectional data in Study 1 and again using longitudinal data in Study 2. Third, a moderation hypothesis was tested on the temporal relationship between purpose and psychological well-being, specifically that the relationship would be stronger for those high in self-transcendent life goals. Finally, Study 3 tested an intervention hypothesis to see whether engaging in deep reflection on and discussion about one's life goals can increase purpose and, consequently, psychological well-being. The results showed partial confirmation of the hypotheses. The cross-sectional analyses showed strong relations among meaningful engagement, purpose, and psychological well-being, and provided support for the proposed mediational model. However, the longitudinal analyses did not show significant relations among the constructs. The moderation hypothesis provided evidence that the path from purpose to well-being was stronger for those high on self-transcendent life goals, suggesting psychological benefits of pursuing purposes beyond oneself (but not self-oriented life goals). Finally, there was a significant positive effect of engaging in deep discussion and reflection on one's life goals, toward both increased purpose and increased psychological well-being. Implications of these findings for higher education in particular are discussed, and directions for future research are presented.