This research integrates several social psychological theories and the life course paradigm to address how adolescents construct and manage their identity in the transition to young adulthood. The larger goals are to inform the study of adolescent identity by drawing upon sociological perspectives of identity and to enhance these same perspectives through insights gleaned from the study of adolescents. To accomplish this objective, three distinct analytic projects are undertaken. The first of these projects proposes a theoretical incorporation of the life course paradigm into identity theory. The analyses assess this integration by investigating adolescent religious identity, focusing on how this identity is maintained through major life transitions, such as a parental divorce or leaving the parents home. The findings suggest that identity theory is a valid theory of adolescent identity, but the connections between its primary mechanisms alter when adolescents make a significant step towards adulthood. The second project extends the investigation of change and stability in adolescent identity by analyzing adolescent social type identities (e.g., Jock or Nerd). This study examines the degree of change in these identities, as well as comparing the influence of ascribed versus achieved factors' influence on each potential identity alteration. Collectively the results indicate about half of all adolescents change identities over a one year period, and achieved factors play a more significant role than ascribed characteristics in determining the likelihood that adolescents assume particular identities. Unique combinations of these two types of factors, however, produce multiple pathways that consistently lead adolescents into the Normal identity. The final project focuses on understanding how adolescent identities may impact young adult trajectories. Specifically, this project investigates how the status of adolescent identities may contribute to substance use and role instability in young adulthood. The results show that popular adolescents are more likely than low status adolescents to binge drink and suffer from academic and employment role instability in young adulthood. Collectively, these projects enhance the understanding of how identities are managed, maintained, and abandoned over the life course.