A brand strategy is a powerful guarantee for a university to enhance its reputation and sustainable development. An internal brand is the foundation of a university brand. Based on three variables—internal market orientation, teachers’ organizational identity, and teachers’ brand support behavior, a research model is constructed on a university’s internal brand formation mechanisms. To summarize how teachers support the university’s internal brand building, we analyzed the relationship between the three variables. This study used a three-stage sampling survey method to distribute 500 questionnaires and recovered 419 valid samples. The data from the valid questionnaires were statistically analyzed using two software programs—SPSS 24.0 and Mplus 7.2. This survey and analysis found that the three internal market orientation dimensions (internal information collection, internal communication, and feedback) are significantly positively correlated with teachers’ organizational identity and brand support behavior. Teachers’ organizational identity is not only significantly positively correlated with brand support behavior, but also mediates the relationship between the three dimensions of internal market orientation and brand support behavior. Universities should pay attention to the key roles of teachers in brand building and regard internal market orientation as an important tool for internal brand building.