ABSTRACT Exploring the Strategizing of a Human Resource Management Practice by Business Line Managers from a Middle Management Perspective Lihui Zhang, Ph.D. Concordia University, 2023 This Ph.D. research explores the strategizing of a HRM practice from a middle management perspective. Adopting the Strategy-as-Practice perspective (Whittington, 2006) as a backdrop, this research studies both an organization’s practice and its practitioners’ praxis to enact HRM practices. In other words, it examines what middle managers (practitioners) do (praxis) to enact one new performance management practice, and how these activities and processes unfold within internal and external environments to result in specific outcomes. Adopting a grounded theory approach, this research conducts a single case study with a professional service firm (ABC Company) in mainland China. Data are collected mainly by conducting semi-structured interviews with business line middle managers, top management team members, and lower-level employees. Document analysis, observations and subject matter expert meetings are also utilized to complement interviews for data analysis. Applying Floyd and Wooldridge’s (1992) four types of middle managers’ strategic influence that are based on two dimensions (upward vs. downward influence and integrative vs. divergent relative to the strategic intent), middle managers in ABC Company are found to exhibit more divergent influence downward to employees, no obvious divergent influence upward to the TMT, and some degree of integrative influences both downward and upward. The strategizing processes are found to unfold over four phases. In each phase, middle managers’ sensemaking, the following actions and the consequent results reinforce each other to drive the process to evolve to the next phase. After a few years of implementation, ABC company had come to a strategic stalemate with two conflicting performance cultures coexisting, where the intended pay-for-performance culture was not fully established, and it was difficult to go back to its initial pay egalitarianism. The working mechanisms that explain middle managers’ activities and the strategizing processes in ABC Company are represented as four mismatches between: (1) its goals and strategy design, (2) its strategy and human capital, (3) its organization and strategy, and (4) sensemaking and sensegiving. This research has implications for strategic HRM in professional service firms. Firms need to build HRM infrastructure and human capital so as to better involve business line managers in HRM activities.