The first purpose of this study calculated the sustainability index of economic, environmental, social criteria and the sustainability index of the whole manufacturing process conducted by CV. Indo Jati Utama (a wood processing manufacturer in Semarang that sells its products on an export scale). The second purpose of this study calculated the performance importance index of each indicator in each criterion. The last purpose of this study proposed some recommendations to increase the sustainability of the manufacturing process at CV Indo Jati Utama. This study uses the multi-grade fuzzy (MGF) method to calculate sustainability and performance importance index. This study used primary data, collected using questionnaires from five experts (General Manager, Department Head of Marketing, Department Head of Finance, Department Head of Production Planning and Inventory Control, and Department Head of Human Resource). The result of data processing indicated that the sustainability index of economic, environmental, and social and the whole manufacturing production process was 7.48, 7.60, 7.60, and 7.50 successively. Moreover, the result of data processing also indicated that the enterprise should increase the performance of five indicators to get more sustainable, namely, flexibility to change, environmental management, green image, employee compensation practices, and employee career development program.