Information technology (IT) management capabilities have been noted in prior research as having a significant impact on firm performance. However, it is not clear how these capabilities impact firm performance. This research focuses in particular on one salient IT management capability, viz., IT infrastructure capability, and develops a conceptual model linking IT infrastructure capability with firm performance. The model identifies three dynamic capabilities that mediate the links between IT infrastructure capability and firm performance: customer and market focus, process management, and performance management capability. Data from 134 firm and business units is utilized to empirically evaluate the hypotheses derived from this model. The results provide compelling evidence for the mediating effects of these dynamic capabilities. Further, our empirical tests suggest that the mediated effects model is has more validity than a model that posits direct impacts of IT infrastructure capabilities on firm performance. These results have significant implications for future research and practice on how IT management capabilities contribute to the development of business capabilities and enhancement of firm performance.