Objective: This longitudinal study investigated the pathways from childhood socioemotional characteristics and cognitive skills to health behaviours in midlife. Methods: Participants in the Jyväskylä Longitudinal Study of Personality and Social Development (JYLS) were followed from age 8 (n=369) to age 50 (n=271). Outcomes included physical activity, smoking, alcohol consumption and body mass index (BMI) assessed at ages 36, 42 and 50. Predictors were socioemotional characteristics (behavioural activity, negative emotionality, and well-controlled behaviour) and parents’ occupational status collected at age 8, cognitive skills (school success at age 14 and the highest education at age 27) and adulthood personality traits (extraversion, neuroticism and conscientiousness). Longitudinal path modelling was used for analyses. Results: Well-controlled behaviour and extraversion predicted physical activity in women. Behavioural activity predicted alcohol consumption in women and smoking in men. Negative emotionality was not directly connected to health behaviours. Adulthood neuroticism was associated with smoking in men and with alcohol-related problems in both men and women. There were some indirect paths from childhood socioemotional characteristics to midlife health behaviours through cognitive skills. None of the study variables predicted midlife BMI. Conclusions: Childhood socioemotional characteristics have some predictive value on midlife health behaviours, both directly and through cognitive skills.