Optimism and neuroticism have strong public health significance; however, their developmental precursors have rarely been identified. This study examined adolescents’ self-competence and their parents’ parenting practices as developmental origins of optimism and neuroticism in a moderated mediation model. Data were collected when European American adolescents (N = 290, 47% girls) were 14, 18, and 23 years old. Multiple-group path analyses with the nested data revealed that 14-year psychological control and lax behavioral control of both parents predicted lower levels of 18-year adolescence self-competence, which in turn predicted decreased 23-year optimism and increased neuroticism. However, the positive effects of warmth on 18-year optimism were stronger in the context of high maternal and paternal authoritativeness, and the positive effects of warmth on adolescent self-competence was attenuated by maternal authoritarianism. This study identified nuanced effects of parenting on adolescents’ competence and personality, which point to important intervention targets to promote positive youth development.