The Nigerian public sector grapples with inefficiency, low productivity, and poor service delivery, partly due to inadequate staff development programs and low job satisfaction among employees. While existing studies have examined these factors in isolation, there is limited research on their collective influence on employee performance in Nigerian public administration. This study investigates the interplay between staff development, job satisfaction, and employee performance, addressing critical gaps in literature and practice. Using a mixed-methods approach (quantitative surveys and qualitative interviews), the research explores the relationship between staff development and job satisfaction, the impact of job satisfaction on performance, and the challenges hindering effective human resource practices in the public sector. The study is anchored on Human Capital Theory and Herzberg’s Two-Factor Theory, providing a robust theoretical foundation. Expected findings will reveal significant positive relationships between staff development, job satisfaction, and performance, offering actionable insights for policymakers and public administrators. The study contributes to human resource management literature, informs public sector reforms, and proposes strategies for enhancing employee motivation and productivity in Nigeria’s public administration.