Despite a graying workforce and a growing number of workers experiencing work transitions, extant literature has largely ignored the role of age in work transition experiences and its impact on the process of work identity change. In this dissertation I employ an inductive approach to elaborate theory concerning the relationships among work transitions, work identity change, and age. Contrary to what extant literature suggests, the findings of a longitudinal qualitative study of 47 employees at a large financial services firm make clear that the types of work transition (role-based transition vs. membership-based transition) and employees' age (Gen X and Gen Y workers in early adulthood vs. Baby boomer workers in middle adulthood) did not differentiate the overall identity change processes within the organization. Rather, my data suggest that identity change is best captured as change in the direction of employees' work identity narratives. Moreover, different combinations of intrapersonal/temporal, interpersonal/social, and future time perspective mechanisms lead to three types of change in the direction of the identity narratives: adjusting, progressing, and regressing. Further, significant differences between age groups surfaced. My research enriches emerging perspectives on work identity as narrative by proposing a temporally-oriented model of work identity change that bridges past, present, and future identities; and delimits the role of age in identity change during work-related transitions.