Prior research has shown the theoretical importance and empirical feasibility of health lifestyles but has not examined their patterns over the life course or their dynamic associations with socioeconomic status (SES) and adult roles. The authors develop and apply a life-course approach to understanding individuals’ health lifestyles across the transition to adulthood, using U.S. data from the National Longitudinal Study of Adolescent to Adult Health (n = 6,863). The results show that ascribed SES is associated with adolescent health lifestyles, and those health lifestyles are associated with later health lifestyles. The results also demonstrate the developmental specificity of health lifestyles. Dissimilarities and variations in the clusterings of behaviors and their associations with SES, along with patterning of adult roles, support a contextualized, life course–focused interpretation of health lifestyle development. The authors highlight the need for an integrated life-course model of the development of health disparities that combines both stability and change.