BackgroundPreterm and/or low birthweight (PT/LBW) is predictive of a range of adverse adult outcomes, including lower employment, educational attainment, and mental wellbeing, and higher welfare receipt. Existing studies, however, on PT/LBW and adult psychosocial risks are often limited by low statistical power. Studies also fail to examine potential child or adolescent pathways leading to later adult adversity. Using a life course framework, we examine how adolescent problem behaviors may moderate the association between PT/LBW and a multidimensional measure of life success at age 30 to potentially address these limitations. MethodsWe analyze 2044 respondents from a Brisbane, Australia cohort followed from birth in1981–1984 through age 30. We examine moderation patterns using obstetric birth outcomes for weight and gestation, measures of problem behaviors from the Child Behavioral Checklist at age 14, and measures of educational attainment and life success at 30 using multivariable normal and ordered logistic regression. ResultsAssociations between PT/LBW and life success was found to be moderated by adolescent problem behaviors in six scales, including CBCL internalizing, externalizing, and total problems (all p < 0.01). In comparison, associations between LBW and educational attainment illustrate how a single-dimensional measure may yield null results. ConclusionFor PT/LBW, adolescent problem behaviors increase risk of lower life success at age 30. Compared to analysis of singular outcomes, the incorporation of multidimensional measures of adult wellbeing, paired with identification of risk and protective factors for adult life success as children develop over the lifespan, may further advance existing research and interventions for PT/LBW children.