Childhood poverty is associated with poor health in adulthood, but social policies may buffer poverty's long-term harmful effects by providing cash and in-kind resources. This study assessed the long-term health effects of welfare reform, which added work requirements, sanctions for noncompliance, lifetime limits, and family caps to welfare programming in the US in the mid-1990s. Research has found mixed evidence on the short-term health effects of welfare reform, but fewer studies have documented its impacts on health across the life course. This study exploited temporal and state variation in the implementation of welfare reform to examine the association between exposure to welfare reform as a child on self-rated health, psychological distress, and chronic conditions in adulthood using data from the Panel Study of Income Dynamics. We found that welfare reform exposure in early childhood, from conception to age five, was associated with more psychological distress (b = 0.41, 95%CI 0.08, 0.74) and more chronic conditions (b = 0.21, 95%CI 0.10, 0.33) in adulthood. We also found that welfare reform exposure in later childhood, from ages six to 18, was associated with lower likelihood of reporting poor health (b = -0.03, 95%CI -0.05, -0.01), less psychological distress (b = -0.33, 95%CI -0.54, -0.11), and fewer chronic conditions (b = -0.18, 95%CI -0.25, -0.10), which was especially true for non-Hispanic Black and Hispanic individuals compared to non-Hispanic White individuals. Our findings suggest that the difference in outcomes based on age of exposure is related to the ease with which parents fulfill welfare requirements, though more research is needed on possible mechanisms.