Emerging adulthood describes the developmental life stage between adolescence and adulthood, when young people gain important educational and social–emotional skills. Here, we tested to what extent intelligence and personality traits in adolescence, family socioeconomic status (SES), and their interplay predict educational (e.g., educational attainment, degree classification) and social–emotional outcomes (e.g., well-being, volunteering, substance use) in emerging adulthood in a U.K.-representative sample (N = 2,277). Intelligence, personality traits, and family SES accounted together for up to 23.5% (M = 9.7%) of the variance in emerging adulthood outcomes. Personality traits, including the Big Five, grit, curiosity, and ambition, were the most consistent and strongest predictors across outcomes, although intelligence was a better predictor of educational attainment. Intelligence, but not personality, accounted for a significant proportion of the associations between family SES with educational attainment, degree classification, behavior problems, aggression, and volunteering (16.4%–29.1%). Finally, intelligence, ambition, conscientiousness, curiosity, and openness were all stronger predictors of educational attainment at low compared to high SES levels. These significant interactions suggest that these traits may help compensate for family background disadvantage, although the corresponding effect sizes were small (R2 0.4%–3%). Overall, our analyses suggested that there is moderate developmental continuity from adolescence to emerging adulthood. Our findings contribute to understanding the psychological characteristics and structural factors that help emerging adults to become resilient and productive members of society.