This study explored the impact of the opera festival held in Daegu on the city brand of Daegu. In a reality where many local festivals are held but many fail, we looked into how the city's image and the audience's image suitability affect the festival. It can provide implications on the success factors of festivals as city marketing. Using congruence as a key variable, this study analyzed the relationship between attitude toward the festival, attitude toward the city, and intention to visit the city. As a result of the survey, attitudes toward the opera festival had a positive effect on attitudes toward Daegu City, and attitudes toward Daegu City were positively linked to intention to visit Daegu. The congruence between opera and self-image was found to have a positive effect on attitudes toward opera festivals. However, self-image congruence was found to have a negative effect on attitudes toward Daegu city. The congruence of the opera and Daegu images had a positive effect on the opera festival, but had a negative effect on the intention to visit Daegu. These results provide academic implications on the importance of image congruence and provide practical implications for theme selection in festival planning.