To better understand how early work experience shapes subsequent employment outcomes for young people (ages 18 to 20) with disabilities, we analyzed longitudinal data from the Youth Transition Demonstration (YTD) evaluation to test whether the employment experiences of 1,053 youth during the initial year after entry affected their employment during the third year after entry. To derive causal estimates, we used a dynamic-panel estimation model to account for time-invariant unobserved individual characteristics that may be correlated with youth’s self-selection into both early and later employment. We also controlled for other socioeconomic and health factors that may affect later employment. We found that early work experience increases the probability of being employed 2 years later by 17 percentage points. This estimate is an important advancement over the correlational approaches that characterize the current literature and provides stronger evidence that early work experience is a key determinant of subsequent labor market success.