While health inequalities related to race/ethnicity, nativity, and age are well documented, it remains unclear how these axes of stratification combine to shape health trajectories, especially in middle and late life. This study addresses gaps in the literature by drawing on both life course and intersectionality perspectives to understand inequalities in morbidity trajectories. Using growth curve models applied to data from the Health and Retirement Study, I examine the life course patterning of health inequalities among US- and foreign-born non-Hispanic whites, non-Hispanic blacks, and Mexican Americans between the ages of 51 and 80 (N = 16,265). Findings are consistent with premature aging and cumulative disadvantage processes: US- and foreign-born blacks and Mexican Americans experience earlier health deterioration than US-born whites, and they also tend to exhibit steeper health declines with age. Moreover, contrary to the common assumption of monolithic healthy immigrant and erosion processes, results show that these processes are contingent on both race/ethnicity and age: compared with US-born whites, white immigrants have a persistent health advantage, while black and Mexican American immigrants experience a health disadvantage that increases with age. These results suggest that among nonwhite immigrants, the immigrant health advantage may be offset by cumulative exposure to racialized immigrant incorporation processes. A wide array of health-related factors including socioeconomic resources, health behaviors, and medical care account for some, but not all, group differences in morbidity trajectories. Findings highlight the utility of life course and intersectionality perspectives for understanding health inequalities.