This study explored how public financial management (PFM) processes influenced the implementation of Kenya’s 2019 Universal Health Coverage (UHC) pilot in four counties through qualitative interviews and focus group discussions. Findings revealed that while a hybrid planning model combined national directives with county input, rigid budget rules, delayed fund disbursements, reduced facility revenues from user fee removal, and increased service demand constrained effective implementation. The authors conclude that addressing PFM bottlenecks such as timely disbursement, budget flexibility, and local revenue generation is essential for the sustainable scale-up of UHC in Kenya.