The purpose of this research is to better understand the impact of supply chain management (SCM) and flexibility on firm performance, as well as the role of competitive advantage in mediating the model in Indonesian agriculture companies. Companies must apply supply chain management and supply chain flexibility (SCF) to boost industrial competitiveness, which impacts firm performance. To ensure that supply chain management supports the company's strategy, companies must evaluate supply chain concerns. From the literature search, researchers have not found any published studies or articles on SCM and SCF in their influence on firm performance through competitive advantage, specifically for corn companies in Indonesia. The population in this study includes agriculture companies in Indonesia. Sampling was carried out using probability sampling technique, the total population of 200 obtained a sample size of 133.333 which can be rounded up to 134 research samples. The inferential statistical method used in the data analysis of this study was the Partial Least Square Version 3 program. The study found that SCM influenced firm performance and SCF had a direct influence on firm performance. However, competitive advantage variable failed in being a mediator in SCM and SCF on firm performance.