Nordic welfare states have been very successful at reducing poverty and inequality among their citizens. However, the presence of a strong social safety net in these countries has not solved the problem of socioeconomic exclusion, manifesting in such outcomes as chronic unemployment and welfare dependency. In an effort to understand this phenomenon, the current study builds on the assumption that psychological risk factors emerge as important determinants of socioeconomic disadvantage in an environment where ascribed characteristics have less impact on educational and occupational attainment. Using data from Finland, this research examined a life course model linking childhood differences in cognitive skills and antisocial propensity to midlife socioeconomic exclusion. The Jyväskylä Longitudinal Study of Personality and Social Development (n = 369) follows individuals from age 8 (b. 1959) through age 50. Evidence from a structural equation model found support for key theoretical predictions: (a) human capital and antisocial pathways contributed independently to socioeconomic exclusion; (b) the effect of childhood psychological factors on midlife socioeconomic exclusion was mediated by adolescent and adult life course outcomes; and (c) the human capital and antisocial domains intersected such that antisocial children struggled in school as adolescents, which contributed to their persistence in crime and deviance in adulthood—a behavioral pattern that directly increased the risk of socioeconomic exclusion in midlife. In short, the findings suggest that early emerging differences in cognitive ability and antisociality set in motion a process of negative life outcomes with enduring consequences for socioeconomic well-being. The results are discussed from the perspective of sociohistorical context and public policy.