Prior research has shown that person-level characteristics (e.g., temperament, personality) correlate and interact with social-contextual factors (e.g., parent-child relationship quality, antisocial peer affiliation) to predict adolescent substance use, but less research has examined similar processes for adult substance use problems. We addressed this gap by testing for personality × romantic partner context interplay in relation to symptoms of alcohol use disorder (AUD) at ages 24 and 29. Participants were twins in the longitudinal Minnesota Twin Family Study (N = 2,769; 52% female). Results support the corresponsive principle of personality in that we found that key personality traits in late adolescence (low constraint, negative emotionality) predicted subsequent "selection" into key social contexts in early adulthood (poorer quality romantic relationships and greater romantic partner alcohol use), which subsequently reinforced those traits and associated outcomes (including correlated AUD symptoms) through late young adulthood. There were few meaningful gender differences in these associations. There was also no support for the personality × romantic partner context interaction as a significant predictor of AUD symptoms at ages 24 or 29. Taken together with prior studies, these results suggest that such interactions may be less relevant to the development of young adult AUD compared to adolescent substance use problems.