A life span health-behavior model was investigated in this longitudinal study of personality influences on health. Teachers assessed 963 elementary schoolchildren on traits that formed scales assessing the dimensions of the five-factor (Big Five) model of personality. Smoking, alcohol use, body mass index (BMI), and self-rated health were assessed 40 years later in midlife. Childhood personality traits were significantly associated with all 4 outcomes, and the effects were consistently larger for women than men. For men and women, childhood Conscientiousness was associated with less adult smoking and better adult self-rated health and, for women only, with lower adult BMI. Mediation analyses suggested that the effects of Conscientiousness on self-rated health were partially mediated by smoking and BMI. These findings add to the growing evidence that childhood personality traits predict adult health outcomes and are discussed in terms of future testing of the life span health-behavior model.