Enterprise architecture management (EAM) is becoming a widely accepted management approach deemed to improve, among others, the long-term development of organizations’ IT and the performance of corporate IT functions. Profound EAM often requires a significant amount of financial and human resources. Therefore, practitioners and researchers alike aim to understand the mechanisms that lead to the desired benefits. However, the way in which EAM generates value is not yet sufficiently understood and the related research lacks a theoretical foundation. We argue that the resource-based theory (RBT) is well suited to explain the influence of EAM on the performance of corporate IT functions and present a framework that helps elucidate this impact. We report on a single case study that we conducted at a large professional service firm. The empirical results identify a first set of causal relationships between the theoretical framework’s elements. The study's findings make it possible for practitioners to better understand the performance impacts of EAM. This work is part of ongoing exploratory research aimed at explaining the mechanisms through which EAM affects firm performance within a testable theory.