Background National systems-based suicide prevention approaches are increasingly being implemented. Community participation is fundamental to the successful implementation of these approaches, but can be challenging to undertake. We present findings from the evaluation of Australia’s National Suicide Prevention Trial (the Trial). Methods We completed consultations with 127 community members and 46 Primary Health Network (PHN) staff. Thematic analysis was undertaken to understand the process of community participation in the planning and implementation of the Trial. Results Themes were identified regarding: a collaborative PHN; an engaged and passionate community; maintaining engagement; getting the right people involved; and getting stakeholders to work together. Continuous negotiation about Trial ownership, acceptability of the Trial model, and choice of activities was required. Community participation was somewhat challenging for PHNs, taking much longer than anticipated for a range of reasons. Conclusions Future system-based approaches could benefit from the provision of community participation skills training and support to enable a more coordinated, and perhaps more easily achieved, approach to the involvement of community. Despite a long process of relationship building between stakeholders, this led to improved community cohesion and integration in local suicide prevention, ready for future collaborative work.