Existing research rarely examines the social consequences of poor childhood health from a longitudinal perspective. Using data from the British National Child Development Study, I follow a cohort from before birth through middle age to examine whether children's health limitations before and during the educational process predict occupational skill in mid-adulthood, and whether negative consequences are strongest for children in persistently poor health. I also examine whether differences in achievement explain the observed associations, and at what point during the schooling process performance begins to play a large explanatory role. Poor health is strongly negatively related to qualifications in adulthood, particularly for children in persistently poor health. These associations are largely explained by differences in performance early in children's academic careers, before the first important transition point. The relationship between prenatal maternal smoking and mid-adulthood qualifications is more persistent. This article demonstrates that a static conceptualization of childhood health is inadequate to fully understand the dynamic process through which social status and health over the course of childhood have long-run consequences for the adult life course. (Contains 12 notes and 6 tables.)