Introduction
There is an extensive literature on public involvement (PI) in research, but this has focused primarily on experiences for researchers and public contributors and factors enabling or restricting successful involvement in specific projects. There has been less consideration of a ‘whole system’ approach to embedding PI across an organization from governance structures through to research projects.

Objective
To investigate how a combination of two theoretical frameworks, one focused on mainstreaming and the other conceptualizing quality, can illuminate the embedding of positive and influential PI throughout a research organization.

Methods
The study used data from the evaluation of a large UK research collaboration. Primary data were collected from 131 respondents (including Public Advisers, university, NHS and local government staff) via individual and group interviews/workshops. Secondary sources included monitoring data and internal documents.

Findings
CLAHRC‐NWC made real progress in mainstreaming PI. An organizational vision and infrastructure to embed PI at all levels were created, and the number and range of opportunities increased; PI roles became more clearly defined and increasingly public contributors felt able to influence decisions. However, the aspiration to mainstream PI throughout the collaboration was not fully achieved: a lack of staff ‘buy‐in’ meant that in some areas, it was not experienced as positively or was absent.

Conclusion
The two theoretical frameworks brought a novel perspective, facilitating the investigation of the quality of PI in structures and processes across the whole organization. We propose that combining these frameworks can assist the evaluation of PI research.