BACKGROUND: Performance based financing was introduced to Kilifi county in Kenya in 2015. This study investigates how and why political and bureaucratic actors at the local level in Kilifi county influenced the extent to which PBF was politically prioritised at the sub-national level. METHODS: The study employed a single-case study design. The Shiffman and Smith political priority setting framework with adaptations proposed by Walt and Gilson was applied. Data was collected through document review (n=19) and in-depth interviews (n=8). Framework analysis was used to analyse data and generate findings. RESULTS: In the period 2015-2018, the political prioritisation of PBF at the county level in Kilifi was influenced by contextual features including the devolution of power to sub-national actors and rigid public financial management structures. It was further influenced by interpretations of the idea of 'pay-for-performance', its framing as 'additional funding', as well as contestation between actors at the sub national level about key PBF design features. Ultimately PBF ceased at the end of 2018 after donor funding stopped. CONCLUSION: Health reformers must be cognisant of the power and interests of national and sub national actors in all phases of the policy process, including both bureaucratic and political actors in health and non-health sectors. This is particularly important in devolved public governance contexts where reforms require sustained attention and budgetary commitment at the sub national level. There is also need for early involvement of critical actors to develop shared understandings of the ideas on which interventions are premised, as well as problems and solutions.