This study integrates research from strategy, economics, and applied psychology to examine how organizations may leverage their human resources to enhance firm performance and competitive advantage. Staffing and training are key human resource management practices used to achieve firm performance through acquiring and developing human capital resources. However, little research has examined whether and why staffing and training influence firm-level financial performance (profit) growth under different environmental (economic) conditions. Using 359 firms with over 12 years of longitudinal firm-level profit data, we suggest that selective staffing and internal training directly and interactively influence firm profit growth through their effects on firm labor productivity, implying that staffing and training contribute to the generation of slack resources that help buffer and then recover from the effects of the Great Recession. Further, internal training that creates specific human capital resources is more beneficial for prerecession profitability, but staffing is more beneficial for postrecession recovery, apparently because staffing creates generic human capital resources that enable firm flexibility and adaptation. Thus, the theory and findings presented in this article have implications for the way staffing and training may be used strategically to weather economic uncertainty (recession effects). They also have important practical implications by demonstrating that firms that more effectively staff and train will outperform competitors throughout all pre- and postrecessionary periods, even after controlling for prior profitability.