This study aims to identify and prioritize the key components influencing sustainable economic performance in Iranian non-government schools. An exploratory mixed-methods design was employed; qualitative data were collected through grounded theory-based semi-structured interviews with 20 experts in educational economics and management, and quantitative prioritization was conducted using the Best–Worst Method (BWM). BWM results indicated that sustainable financing had the highest weight among causal conditions, followed by sustainable human resource management and sustainable quality development. At the contextual level, the national economic situation exerted the strongest influence, while economic fluctuations and the institutional–legal framework dominated intervening conditions. Among strategic factors, financial and revenue strategies ranked first, and among outcomes, improvement of educational quality received the highest priority. The findings demonstrate that achieving sustainable economics in non-government schools primarily depends on financial stability, effective human resource management, and continuous quality enhancement, providing a robust basis for evidence-based educational policy and school-level decision-making.