This study examines the mechanisms by which different aspects of socioeconomic status affect disability trajectories among older adults. The author conceptualizes and models disability in two life course components, onset and growth, in order to see how socioeconomic status and its mechanisms differ in their effects on the timing and accumulation of disablement. Using the Duke Established Populations for Epidemiologic Studies of the Elderly (EPESE), the author finds that the effects of education are mainly preventive for disability onset where financial resources both delay and ameliorate a trajectory of disability accumulation after onset. Health behaviors and mastery work as independent mediators of education while financial-based capital works to mediate both income and education effects. This study highlights transitions and trajectories in health processes, showing that education effects are far reaching and robust but only work for onset, while financial-based capital is effective in ameliorating a trajectory of disability in later life.