Prior research suggests that the construct of leadership and theory surrounding knowledge in terms of its content, use, and role within the organization are complex. Leadership spans many levels of analysis and can be approached from different perspectives and disciplines. However, to date no research has empirically explored the leadership construct and how it contributes to communication effectiveness from the perspective of public relations practice. Thus, the attempts made here are to define the construct of excellent leadership in public relations, to identify its key dimensions, and, more importantly, to develop measurement scales of the constructs from the perspective of quantitative methodology. More specifically, this dissertation addresses the following five questions: (1) How is excellent leadership defined in public relations? (2) As a complex, multifaceted phenomenon, what key dimensions does the construct of leadership in public relations encompass? (3) How are organizational structure and culture related to the achievement of excellent leadership in public relations? Given the importance of cultural influence on leadership effectiveness, (4) Are some dimensions of excellent leadership in public relations universally relevant while some are culturally specific? and (5) What core values and qualities of public relations leadership do different cultures emphasize? In order to answer these questions, both quantitative and qualitative research phases are involved. The first phase involves online surveys to different groups of public relations practitioners in multiple locations. The conceptual measurement model and structural model are tested by using the collected quantitative data. In the second phase, in-depth interviews with senior public relations executives in the U.K. and Singapore are conducted and the results further strengthen the findings revealed at the quantitative phase. Overall, the research findings present strong evidence regarding the multi-faceted nature of the leadership construct itself and indicate that the key dimensions of leadership are largely complementary and related in a meaningful way. Moreover, the impact of organizational structure and culture on the achievement of excellent leadership in public relations is confirmed and discussed. In sum, findings from this study will help enhance the theoretical development of leadership research in public relations, as well as provide concrete directions and managerial guidelines for public relations industry.