This study examined public health expenditure, budget realism, and health outcomes in north-eastern Nigeria: evidence from a mixed-methods analysis (2021–2024). This research was inspired by the fact that the high rates of poor health in the area have not improved despite the rising government expenditure on health. The primary aim was to determine how the expenditure and budget realism on public health affect health results. An integrative design was embraced with quantitative analysis of secondary data integrating with qualitative data through policy reports. The analysis of the data was done with the help of descriptive statistical and regression methods. Results suggested that despite the growth in public health spending over the years, budget realism combined with inefficiencies in the use of funds, constrain the effect of public health expenditure on health outcomes. The research found that to get better health outcomes, it is necessary to strengthen the credibility of budget and to improve the mechanism of governance. It was also advised that policymakers should increase transparency, accountability, as well as alignment between budgetary allocations and real expenditures in the health sector.