Educational attainment and occupational status are key markers of success in adulthood. We expand upon previous research that focused primarily on the contributions of academic competence and family socioeconomic status (SES) by investigating the role of mental health in predicting adult SES. In a longitudinal study spanning 30 years, we used structural equation modeling to examine how parental mental health in early childhood and family SES, offspring academic competence, and offspring mental health in adolescence relate to occupational and educational attainment at age 30. Results were that adolescent academic competence predicted adult educational attainment, and that educational attainment then predicted occupational attainment. The pathways between academic competence and occupational attainment, family SES and educational attainment, and family SES and occupational attainment were not significant. In contrast, adolescent mental health not only predicted educational attainment, but was also directly related to adult occupational attainment. Finally, early maternal mental health was associated with offspring's adult socioeconomic attainment through its relations with adolescent academic competence and mental health. These results highlight the importance of mental health to adult socioeconomic attainment.