The main purpose of the study was to find out how task and contextual performance within organizations can be improved so as to achieve sustainable organizational performance. The study indicates that increasing task performance, which is about good implementation of formal job responsibilities, might result in favorable outcomes for sustainable organizational performance. Similarly, promoting contextual performance, which involves extra-role behaviors contributing to efficient organization operation, may also improve sustainable organizational performance. However, essentially, the research is all about raising both dimensions. This study aims at exploring the relationship between External Locus of Control (LOC), task performance and contextual performance among employees. The research design used was descriptive while data for the study was collected using convenience sampling method from 170 middle level managers of banks in Pakistan. After collecting data using a modified questionnaire, IBM SPSS 20.0 and AMOS 20.0 were used to analyze it. To conduct this analysis regression analysis was applied.