Medium and large industries are vital businesses that have an important role in economic development and growth in Indonesia, with abundant job opportunities available in these industrial sectors. This study aims to examine the effect of supplier integration, internal integration, and relationship management to customer relationships on operational performance and business performance, and the role of operational performance variables as a mediation. The data taken were 210 respondents involved in various industries in Central Java, Indonesia and then analyzed and processed using IBM SPSS Statistic software version 24 and Smart PLS 3.0 (Smart Partial Least Square). The sampling technique used in this study was purposive sampling. Data obtained directly from respondents who met the characteristics of the population determined by distributing questionnaires. Based on the test analysis results, it was found that the supplier integration, internal integration, and relationship management to customer variables had a significant positive relationship on operational performance and business performance. It was also observed that operational performance mediated the effect of supplier integration, internal integration, and relationship management to customer on business performance.