This dissertation examines how employee selection practices are mediated by idea-tional and material tools based on an ethnographic study across multiple organizations. Prior research has demonstrated that employee selectors rarely adopt the “best practice” approach established by psychometric research. Yet little is known about why selectors refrain from following research-based recommenda-tions, or how they conduct employee selection instead. With this analytical tension as a backdrop, the dissertation adopts a practice-based approach to pursue the fol-lowing research question: How do ideational and material tools mediate the performance of employee selection? The dissertation comprises three papers con-ceptualizing employee selection as routine, practice, and process, respectively, to investigate how the actions of selectors are mediated by different cultural means.