The shift of Corporate Social Responsibility (CSR) from a voluntary commitment to a business strategy and regulatory obligation has increased the need for measurable assessments of the social and environmental impacts of corporate sustainability initiatives. This study evaluates the effectiveness and the social, economic, and environmental value created by the KIJANGKU (Konservasi Hijau Selamatkan Lingkunganku) Social Innovation Program, implemented by PT Toyota Motor Manufacturing Indonesia (TMMIN) at Karawang Plants 1–2 during 2023–2025. Using the Social Return on Investment (SROI) approach, the study assesses the value generated relative to the program’s social investment. A total investment of IDR 381,000,000 (present value: IDR 399,237,600) produced benefits with a present value of IDR 524,762,076, yielding an SROI ratio of 1.31. Each IDR 1 invested thus generated approximately IDR 1.31 in social, economic, and environmental value. The findings indicate that KIJANGKU benefited local communities while supporting environmental conservation and sustainability. The study highlights the applicability of SROI for evaluating the broader impacts of corporate social innovation programs and their contribution to the Sustainable Development Goals (SDGs), including SDG 1 (No Poverty), SDG 8 (Decent Work and Economic Growth), SDG 13 (Climate Action), and SDG 17 (Partnerships for the Goals).