The two essays of this dissertation focus on the influence of supply chain and operations management executives on the firm’s supply chain strategies. Essay 1 focuses on the differences in the supply chain and operations management role and investigates how these differences impact the firm’s supplier portfolio management strategies. Essay 2, in turn, investigates the impact of a chief supply chain officer on a firm’s inventory investment when the firm pursues a global sourcing strategy. Both Essays 1 and 2 leverage archival data and econometric data analysis to further the debate in supply chain and operations management research. Essay 1 of the dissertation is grounded in upper echelons theory (UET) and analyzes how differences in the supply chain and operations managers on the firm’s top management team (TMT) impact the firm’s strategic supplier portfolio management (SPM). Strategic SPM requires the firm to set up plans for its supply base as a whole as well as the individual relationships with its suppliers. Two of the key aspects of this are the firm’s geographic sourcing strategy that impacts the firm’s supply base and the firm’s supplier relationship strategy that impacts the firm’s relationships with its individual suppliers. These strategic choices impact the firm’s supply chain and operations and will thus be influenced by the supply chain and operations managers on the firm’s TMT. At the same time, the main difference between supply chain management and operations management lies in the focus of each of these disciplines – operations management emphasizes optimizing the firm’s internal cross-functional processes, while supply chain management centers on optimizing processes within the context of the firm as a part of the whole supply chain. So, leveraging UET, I argue that these differences lead the supply chain and operations managers to significantly different strategic SPM decisions. To assess the validity of my claims, I use various econometric techniques to analyze a panel dataset of 14,530 observations of buyer-supplier dyads over four years. This panel dataset is based on consolidated data from Compustat, Bloomberg’s SPLC module and Bloomberg’s executive database. The results provide consistent support for the hypothesized theory that the differences in supply chain and operations management lead to significantly different outcomes. Essay 2 of my dissertation juxtaposes agency theory and upper echelons theory (UET) to analyze how a chief supply chain officer (CSCO) on a firm’s top management team impacts its inventory investment when it pursues a global sourcing strategy. Using Agency Theory, I argue that firm’s pursuing a global sourcing strategy are exposed to increased supply uncertainty from risk sharing and agency problems. This increased uncertainty leads to a need for increased inventory buffers. Next, supported by UET, I build my hypothesis that a CSCO on the TMT results in lower inventory investments by focusing on reducing the firm’s exposure to uncertainties. Furthermore, given their insights into supply chain relationships, CSCOs are uniquely suited to improve collaboration, coordination and information sharing with its global sourcing partners, leading to lower uncertainties and thus lower inventories. To assess the validity of my claims, I use different econometric techniques to analyze a panel dataset of 2,883 observations over five years. I assembled this panel dataset by consolidating data from Compustat, Bloomberg’s SPLC module and Bloomberg’s executive database. I demonstrate that firms with a chief supply chain officer on their TMT have lower inventory investments when the firm pursues a global sourcing strategy.