Increasingly, Design Thinking's influence reaches beyond the confines of traditional design disciplines and expands its role in connecting domains and integrating resources. This study focused on the changing role of design researchers involved in interdisciplinary research projects, following a Research-through-Design (RtD) approach. The research setting for this study was a project on the design and evaluation of digital solutions in the context of dementia. This study applied process research methods to provide a holistic view of the dynamics between actors from different domains as well as an understanding of the role of design researchers within the complexity of the larger system of an interdisciplinary RtD collaboration. Findings at the organizational, process, and product levels emphasized the following three changing roles for design researchers in interdisciplinary RtD: (1) a mediator role, (2) a sensemaking role, and (3) a role in improving processes by applying research artefacts.