Corporate social responsibility (CSR) involves multiple activities and is influenced by the cultural and legal environment of the country in which a firm is located. This study examines the role of audit committees’ (AC) financial expertise in the relationship between CSR and the earnings quality of Korean firms with high levels of CSR. Using a multivariate analysis, it investigates whether the ACs that include members with accounting expertise, finance expertise, or supervisory expertise individually affect a firm’s decision making. It also examines how ACs with diverse expertise contribute toward improving the financial reporting quality of firms with high levels of CSR. The results demonstrate that when there is a certified accountant in the AC of a firm that practices CSR based on ethical motivation, the earnings management through discretionary accruals is more strictly controlled. This is more effective when the AC comprises members with accounting and non-accounting expertise. This finding implies that the AC plays a positive role in improving the accounting information quality of firms with CSR excellence. Moreover, while the role of accounting experts in the AC is important for maintaining high earnings quality, combining other types of expertise creates synergy.