We examine whether more able bank-managers achieve better performance, and if so, whether their superior performance is attributable to the bank expansion and revenue-diversification strategies. To examine those research questions, we modify a measure of managerial ability introduced by Demerjian et al.(2012) to fit in the banking industry. Our results are as follow. First, OLS results show that banks with more able managers are associated with better performance. The Korean government has made an effort to create a competitive environment in banking industry(i.e., the bank reform) since the 1998 asian financial crisis. Our results imply that managers of each bank have an important role in the management of the bank, such as common industry, and that the environment where bankmanagers can exert their competence was created after the crisis. Second, the results of structural equation model show that the bank expansion and revenuediversification strategies of superior managers have positive effects on the bank performance. Specifically, the results indicate that the positive relation between bank-managers’ ability and bank performance is mediated by the expansion and diversification strategies. Considering that bank-managers plan and implement management strategies, those results imply that more able managers can formulate more profitable expansion and diversification strategies. Our study contributes to the banking industry practice, such as an appointment of bank managers. Despite of the Korean government’s effort to grant a management autonomy after the 1998 asian financial crisis, the press and media still have a doubt on the appointment process of bank managers. Our results that bank performance varies with the bank-managers’ ability imply that the election process of bank-managers should be transparent, and that wellqualified candidates based on objective criteria should be appointed to bank-managers.