Research shows that sports participation in youth is associated with earnings in adulthood. However, studies have often relied on self-reported earnings and on single indicators of sports participation. Using large-scale data linked to administrative records, we investigate: (a) whether sports attitudes at age 13 are uniquely related to income at ages 30–36 and (b) whether educational attainment and mental health in early adulthood mediate this association. We find that a one SD increase in sports attitudes is related to a 10% increase in income. This association is not entirely confounded by preexisting and co-occurring risk factors. Educational attainment mediates 22% of the association between sports attitudes and income. Sports attitudes are potentially a form of capital deployed in the pursuit of socioeconomic advantages.