In this article, I make the case for using an integrative approach to health, broadly defined as social, emotional, mental, and physical well-being; for studying health among the young as an important marker for future health and well-being across the life course; and for understanding health disparities among the young as both causes and consequences of social stratification. An integrative approach bridges biomedical sciences with social and behavioral sciences by understanding the linkages between social, behavioral, psychological, and biological factors in health. It is furthermore vital that integration occur in all steps of the research process: in theory, design, data collection, and analysis. I use the National Longitudinal Study of Adolescent Health, or Add Health, as an example of an integrative approach to health and of the importance of adolescence and the transition to adulthood years for setting health trajectories into adulthood. Evidence is also presented on the linkages between health trajectories during adolescence and the transition to adulthood and social stratification in adulthood.