In this thesis I discuss how change in the construction sector affects and is affected by individuals’ perceptions and actions. Previous research has shown that behavioral change at the individual level is needed to achieve change at the macro level. This thesis therefore highlights continuous change from a professional perspective. Specifically, it focuses on the change phenomena of fragmentation, digitalization, and sustainabilization,and is thus connected to ongoing debates in research on how to ‘manage fragmentation’ or ‘achieve digitalization and sustainability’. Some previous studies in these areas rely on assumptions that are problematized and presented in a new light in this thesis. By focusing on professionalization, the thesis unveils the complex and reciprocal relationship between these change phenomena. Previous research has rarely analyzed fragmentation, digitalization, and sustainabilization together, especially from a professionalization perspective. The thesis therefore fills a research gap while simultaneously addressing highly relevant issues that are discussed daily at individual, organizational, and sectoral levels.The thesis focuses particularly on the architectural profession. This is partly because increasing fragmentation has significantly altered the role of architects in construction projects, not least because they are seen as central actors in driving digitalization and sustainability efforts. However, the focus on architects is also motivated by their under-representation in existing research. The theoretical points of departure are institutional theory (with a focus on agency) as well as sociological concepts related to professional identity and professional roles.Methodologically, the thesis builds on interpretive qualitative studies at the individual level, where focus groups, interviews, and shadowing have been used. In total, 41 architects participated in these studies, sharing their perceptions of themselves and their everyday practices in construction projects.By focusing on the professionalization underpinning larger structural changes—fragmentation, digitalization, and the sustainability transition—the thesis explores new perspectives. It discusses: the nature of fragmentation (from static to dynamic); the impact of fragmentation on digital and sustainability change (from barrier to enabler); how fragmentation can be managed (from the architect’s perspective); professional roles (from fixed to flexible); the profession (from uniformity to diversity); agency (from “cultural dopes” via entrepreneurs to implicit agents); professional identity (from partly unexplored to a central source of institutional change); as well as how digitalization and the sustainability transition can be understood as institutional movements.The thesis contributes empirically to theoretical fields such as research on professions and institutional theory (especially concerning agency and institutional work). It also offers new perspectives on long-standing challenges within construction research. For example, the results show the significance of professional identity for achieving institutional change in the construction sector, as well as how professionals cope with, navigate, and adapt to continuous change—insights that are central for understanding and practically managing fragmentation.Finally, with this thesis I hope to contribute to a renewed discussion about the development and future of the architectural profession, as well as the need to consider individual experiences to understand larger structural phenomena.