Given that consumers’ awareness of a company’s positive ESG activities can help improve the image and value of such a company, it raises the need for research that examines the role of consumer awareness in the relationship between ESG competency and firm value. This study examines the relationship between ESG competency and firm value by looking at the customer’s awareness. The analysis showed the following two results. First, among ESG competencies, the environment and social evaluations had significantly positive effects on firm value, while the governance structure evaluation had no significant effect. In other words, a company’s environmental and social competence, excluding that of corporate governance, is valuable information in enhancing its firm value to the stakeholders. Second, the effect of ESG competency on corporate value highly depends on the level of consumer awareness. In other words, the higher the level of consumers’ awareness of ESG competency, the more significant the effect of ESG competency on the firm value. This study provides a variety of practical implications to corporate decision-makers by empirically verifying the effect of a company’s ESG competency on its firm value and looking at ways to maximize such effect.