The time between adolescence and adulthood is a transformative period of development. During these years, youth are exploring work, relationships, and worldviews while gaining the capacities needed to take on adult roles. These social and psychological processes are reflected in how personality develops across this period. Most youth personality development research has focused on the Big Five domains, ignoring the hierarchical structure of personality and missing broader, higher order processes and more specific, lower order processes. Toward a more comprehensive account, this study examines how personality develops from adolescence into the early years of adulthood at the metatrait (stability, plasticity), domain (Big Five), and facet levels. Data come from a longitudinal study of Mexican-origin youth (N = 645) with few socioeconomic resources who were assessed 5 times from Ages 14 to 23. We used latent growth curve models to investigate mean-level change, rank-order consistency, and the maintenance of trajectories for self-reported personality metatraits, domains, and facets. We found distinct developmental processes unfolding at each level of the hierarchy, including (a) mean-level changes in the metatraits and domains indicating increases in exploratory tendencies (i.e., plasticity) and maturity (i.e., increases in agreeableness and conscientiousness, decreases in neuroticism), and divergent change patterns between facets within each domain indicating nuanced maturational processes; (b) comparable levels of rank-order consistency for metatraits, domains, and facets; and (c) evidence that deviations from youth’s developmental trajectories did not persist over time. Our findings offer insights into personality development that would be impossible to glean from the domain-level alone and adds needed sociocultural diversity to the literature.