This paper is the first to use a randomized trial in the US to analyze the short- and long-term educational and employment impacts of an after-school program, the Quantum Opportunity Program, that offered disadvantaged high-school youth: mentoring, educational services, and financial rewards with the objective to improve high-school graduation and post-secondary schooling enrollment. Average impacts reveal that the hefty beneficial educational outcomes quickly faded away. Heterogeneity matters. While encouraging results are found for the younger youth; detrimental long-lived outcomes for males suggest that extrinsic rewards may be crowding out intrinsic motivation. Evidence by sites' funding source, which led to implementation differences, supports this hypothesis.