Research on the professional development of school leadership often highlights the value of partnerships across institutions. Increasingly, partnership has been labeled boundary work. However, few empirical studies have been conducted on school leaders' professional development as boundary work. The aim is to contribute empirical insight into the phenomenon based on a specific case and present findings from a qualitative study. The study is grounded on audio and video data collected over a 2-year period in a team of participants from schools, a local educational authority, and a university in Norway. This enables attention to the minute details of participant discursive initiatives and interactions. The third generation of the cultural historical activity theory (CHAT) is the chosen theoretical framework. Through extensive coding of discursive individual initiatives during 10 meetings, the analysis revealed 13 types of initiatives and their patterns of distribution across the three institutions. The interaction analysis shows how the different initiatives contributed to an expansion of the problem-spaces being worked on and how the issues of leadership, power, and authority emerged in the interactions. Attention to the initiatives and the interactions is essential to ensure that boundary work aids school leadership development in the future.