Background: Public involvement is increasingly considered a prerequisite for high-quality research. However, involvement in palliative care is impeded by limited evidence on the best approaches for populations affected by life-limiting illness. Aim: To evaluate a strategy for public involvement in palliative care and rehabilitation research, to identify successful approaches and areas for improvement. Design: Co-produced qualitative evaluation using focus groups and interviews. Thematic analysis undertaken by research team comprising public contributors and researchers. Setting/participants: Researchers and public members from a palliative care and rehabilitation research institute, UK. Results: Seven public members and 19 researchers participated. Building and maintaining relationships, taking a flexible approach and finding the ‘right’ people were important for successful public involvement. Relationship building created a safe environment for discussing sensitive topics, although public members felt greater consideration of emotional support was needed. Flexibility supported involvement alongside unpredictable circumstances of chronic and life-limiting illness, and was facilitated by responsive communication, and opportunities for in-person and virtual involvement at a project- and institution-level. However, more opportunities for two-way feedback throughout projects was suggested. Finding the ‘right’ people was crucial given the diverse population served by palliative care, and participants suggested more care needed to be taken to identify public members with experience relevant to specific projects. Conclusion: Within palliative care research, it is important for involvement to focus on building and maintaining relationships, working flexibly, and identifying those with relevant experience. Taking a strategic approach and developing adequate infrastructure and networks can facilitate public involvement within this field.