This study was conducted with the assumption that good corporate governance and corporate social responsibility in organizations will help organizations achieve long-term sustainability. Previously, good corporate governance and corporate social responsibility were primarily applied to corporations with the goal of remaining profitable, whereas non-profit organizations must remain financially viable in order to serve their members and communities. The focus of this study is on the church as a religious institution that also serves as a non-profit corporation. Data was gathered using a quantitative and qualitative mixed method approach. The quantitative data analysis method employs Ritchie and Kolodinsky's Financial Performance Ratios, which include Fiscal Performance, Public Support, and Investment Performance Ratios, as well as an interpretative paradigm with ethnographic methods for qualitative research. The study's findings demonstrate that financial performance, as evaluated by Ritchie and Kolodinsky financial ratios, has been erratic, with a propensity to decline in 2017 due to a change in church management. The interviews revealed that the Church of Batak Karo Protestant practices good corporate governance and corporate social responsibility, which have a favourable impact on financial performance. To gain public trust, the Church of Batak Karo Protestant must continually enhance its Good Corporate Governance and Corporate Social Responsibility. This study also found that the Karo tribe's culture has a significant impact on the Church of Batak Karo Protestant's application of Good Corporate Governance and Corporate Social Responsibility. The policy recommendations in this study for the Church of Batak Karo Protestant are to establish a standardized and integrated management system that incorporates Good Corporate Governance and Corporate Social Responsibility, as well as the assimilation of Karo culture, based on the findings.