The heterogeneity of the timing and order of achieving the "big five" markers of the transition to adulthood is often treated as a taken-for-granted feature of emerging adulthood, reflecting a tendency of "leisure to explore" between adolescence and adulthood. With the central assumption of emphasizing how individuals take greater control of personal biographies in postmodern societies, the individualization thesis has also received wide acknowledgment in conceptualizing the changing patterns of the life course, especially when accounting for the growing heterogeneity in the pathways to adulthood. The first substantive chapter of this dissertation identifies an individualization-heterogeneity nexus in the current life course research on the transition to adulthood. It interrogates the conceptual pitfalls that distract researchers from understanding the real source of heterogeneity observed in the pathways to adulthood. The illustrative example shows that educational attainment stratifies the level of heterogeneity in school-to-work and family formation trajectories, which challenges the notion that individualized choice-making leads to the de-standardization of transition patterns. The two empirical chapters examine how structural inequality shapes early work-family trajectories and reveal how "failure to launch" pervades in an age of expanding precarity in the youth labor market. Using data from the National Longitudinal Survey of Youth (1979 & 1997), the first empirical study compares the work-family trajectories between Late Baby Boomers and Early Millennials. By employing multichannel sequence analysis, this study identified seven distinct transition patterns reflecting mutual reinforcement of domain-specific dis/advantages. The cohort comparison suggests that Early Millennials are more likely than Late Baby Boomers to enter work-family trajectories characterized by labor market precarity, and there is no declining relevance of stratifying mechanisms such as gender and family background. The second empirical study documents the extent to which the two non-college-bound groups, i.e., high school graduates and GED recipients, are disconnected from the labor market throughout the entire early career among Early Millennials. It also identifies a substantial HS-GED gap in the labor market connection associated with multiple risk factors initially related to high school dropout. In sum, this dissertation conceptually clarifies and empirically tests how precarity drives the observed heterogeneity in the transition to adulthood. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]