This study examines the extent to which the ESG scores of Korean listed firms reflect disclosure, controversies, and ownership structure. We use ESG scores from the Korea Institute of Corporate Governance and Sustainability (KCGS), Sustinvest, S&P Global, and Bloomberg for KOSPI-listed firms over the period 2015–2024, converting each into annual percentile rank scores. Our main findings are as follows. First, a KCGS-based disclosure index explains ESG scores, although this result depends on the choice of disclosure measure. Second, ESG scores show no negative association with the occurrence of ESG controversies in the following year; that is, the risk-identification function of ESG scores is not confirmed. Third, the positive association between foreign ownership and ESG scores is significant and consistent with a pattern of partial mediation through disclosure levels. In contrast, no such pattern is observed for institutional ownership. Fourth, the greenwashing hypothesis is not supported, although statistical power is limited in the controversy sample. Taken together, these results suggest that ESG scores do not function as risk signals and depend substantially on disclosure levels.