Amidst the intense competition in the petrochemical industry, the determinants of sustainable customer loyalty remain underexplored. This study investigates the factors influencing corporate sustainable customer loyalty, focusing on service innovation, product quality, and corporate image, with customer satisfaction as a mediating variable. In the context of intense competition, understanding these factors is crucial for sustaining customer relationships and ensuring long-term success. The primary aim is to explore how these elements interact to shape sustainable customer loyalty. Using a cross-sectional survey method, data were collected from 120 corporate clients through structured questionnaires. The study employed Partial Least Squares Structural Equation Modeling (PLS-SEM) to analyze the relationships between the variables. The findings reveal that product quality significantly impacts both customer satisfaction and loyalty, highlighting its pivotal role in meeting customer expectations and fostering long-term relationships. While service innovation does not directly affect immediate satisfaction, it significantly enhances sustainable customer loyalty, indicating its importance for long-term engagement. Corporate image also plays a crucial role in strengthening sustainable customer loyalty, underscoring the value of maintaining a positive reputation. The study concludes that customer satisfaction mediates the relationship between product quality and loyalty, emphasizing the cyclical nature of these constructs. This research fills a notable gap in the literature by providing a comprehensive model that integrates these variables within the petrochemical industry context, offering new insights into effective sustainable customer loyalty strategies.