Private sector related to the agrochemicals plays a vital role in the agrochemical industry in Sri Lanka. There is a huge competition among agrochemical companies in Sri Lanka. Employee’s performance is the key driving force for the market competition and productivity of the company. Analysing the discrepancy between potential and actual performance of the employees is crucial for those agrochemical companies. Hence, this research focused to identify the determinants of the discrepancy of employee performance and to identify the impact of employer’s strategic role behavior on performances. One of the leading private sector agrochemical Company in Sri Lanka was purposively selected for this study. Primary data was collected from randomly selected 50 employees using structured questionnaire. Standard statistical procedures, such as regression analysis, Pearson correlation analysis and Wilcoxon sign rank test were employed to analyze the data. The study concluded that employee’s personal determinants namely employees experience, skills, motivation and confidence are significantly affect for the discrepancy of employee performances while managerial role on employees performances namely organizing procedure, delegation, authority distribution and management, coordination among employees have significant negative impact on employee performances(p=0.000). According to the Pearson correlation analysis, the age of the employees have significant correlation with employees work load & schedule. Past experience of the employees have significant correlation with role ambiguity, employees planning ability, skills of the employees, confidence and the motivation of the employees. Furthermore, this study suggested that organization management in agro chemical companies must focused on employee’s personal factors and managerial behavior apart from strategic role behaviour in order to improve the employee’s performance effectively. Keywords: Agro chemical company, Employee performances, Human resource practices, Strategic human resource management, Strategic role behavior