Internal risk control systems are critical to the banking industry, since most of their business activities are prone to several risks. However, the internal risk control systems of most banks have not been customised to suit their business activities to mitigate the risks associated with their business operations. Given this, this study used the five COSO internal control components to assess the impact of custom-made internal risk control systems on bank performance, which was intended to provide comprehensive knowledge. The 10-year study from 2012-2021 is made up of 20 commercial banks, 10 savings and loans, 10 microfinance companies and 10 rural and community banks. Data was collected by means of a close-ended questionnaire designed on a five-point Likert scale, where ‘strongly agree’ and ‘agree’ were scored (1), whereas ‘neither agree nor disagree’, ‘disagree’ and ‘strongly disagree’ were scored (0). The secondary data was obtained from the audited annual reports of the banks using the Orbis database. The study used return on assets (ROA) as the performance indicator, and employed a custom-made control environment, risk assessment, control activities, monitoring, net interest margin, and custom-made information and communication as the independent variables. The study used descriptive statistics, correlation matrix, tolerance value, variation inflation factor, Cronbach’s alpha, OLS, FE and system GMM in its analysis. The study found that the custom-made control environment, risk assessment, control activities, monitoring, net interest margin, and custom-made information and communication positively impact the return on assets, i.e. profitability. The study provided knowledge on the impact of custom-made internal risk control systems on bank performance. The study suggests that banks should identify and capitalise on the best mix of internal controls that suit their business environments and objectives. The imminent research can broaden the scope of the study by including (ROE), (NIM), or (CTI) as performance indicators in other organisations and economies.