Background: Since the inception of Primary Health Networks (PHNs) in Australia, it has been unclear what their role is regarding implementing chronic disease prevention activities in general practice. This study aimed to qualitatively explore the views of PHN staff on the role of PHNs in promoting prevention, with a focus on cardiovascular disease (CVD) prevention.Methods: Content analysis of PHN Needs Assessments was conducted to inform interview questions. 29 semi-structured interviews were conducted with 32 PHN staff, between June and December 2020, in varied roles across 18 PHNs in all Australian states and territories. Transcribed audio-recordings were thematically coded, using the Framework Analysis method to ensure rigour.Results: We identified three main themes about the role of PHNs in promoting, supporting, and improving CVD prevention. 1) Informal prevention: All respondents agreed the role of PHNs in prevention was indirect and, for the most part, outside the formal remit of PHN Key Performance Indicators (KPIs.) Nevertheless, prevention activities were conducted in partnership with external stakeholders, professional development and quality improvement programs, and PHN-funded data extraction and analysis software for general practice. 2) Constrained by financial incentives: Most interviewees felt the role of PHNs in prevention was contingent on the financial drivers provided by the Commonwealth government, such as Medicare funding and national quality improvement programs. 3) Shaped through competing priorities: The role of PHNs in prevention is a function of competing priorities. There was strong agreement amongst participants that the myriad competing priorities from government and local needs assessments impeded prevention activities.Conclusions: PHNs are well positioned to foster prevention activities in general practice and local communities. However, we found that PHNs role in prevention activities were informal, constrained by financial incentives, and shaped through competing priorities. Prevention can be improved through a more explicit prevention focus at Commonwealth government level. To optimise the role of PHNs therefore requires prioritising prevention, aligning it with KPIs, and supporting stakeholders like general practice.