In an era of hypercompetition, research and development (R&D) investments are vital for organizations to stay competitive. This microlevel study draws on dynamic managerial capability (DMC) theory to explore the mechanisms contributing to competitive advantages. It posits that DMCs enhance firm performance by increasing R&D spending, and explores the moderating role of slack resources due to their effect on resource availability. Employing hierarchical regression analysis and bootstrapping methods on a longitudinal sample comprising 31 German DAX firms, the findings robustly demonstrate that DMCs facilitate firm performance by fostering R&D expenditures and confirm the moderating effect of specific slack resources. However, only internal but not external slack resources amplify the relationship between DMCs and R&D intensity. Overall, this study emphasizes the critical role of managers’ microlevel capabilities in determining firm performance and sheds light on how different slack resources influence the relationships between DMCs, R&D intensity, and firm performance.