Microfinance Institutions (MFIs) often grapple with allocating adequate resources toward Corporate Social Responsibility (CSR), despite their crucial societal impact. This research investigates CSR assessment and CSR sustainability in the context of strategic CSR-related activities of MFIs, aiming to optimize resource allocation and enhance their CSR initiatives. Data was collected from 875 employees and clients of large MFIs in the Philippines and analyzed using structural equation modeling in AMOS. The findings revealed that CSR assessment and CSR sustainability were significantly linked to strategic CSR-related activities, and CSR assessment had a significant link with CSR sustainability. These findings emphasize the importance of strategic orientation in CSR-related activities and support the logical precedence of Carroll's CSR Pyramid and Battal's CSR Train Theories, which advocate for a balanced approach encompassing economic, legal, ethical, environmental, and philanthropic responsibilities. This study contributes to the literature by exploring strategic and sustainable CSR in MFIs in developing countries, where the topic has not been broadly studied. The results can serve as a reliable basis for ensuring transparency, assessment effectiveness, and the creation of an integrative CSR framework for MFIs.