Studies have shown that project managers are responsible for the successful management of various projects. Increasingly, this success depends on the project manager being a knowledge worker (KW)—i.e., possessing and utilizing both “hard” and “soft” skills/competencies to manage assigned projects. Nonetheless, there has not been enough studies on what these competencies are, especially in the context of developing countries (DCs). This study, therefore, seeks to conceptualize project managers as KWs by identifying the key competencies and their relationships needed to effectively manage projects in DCs. To achieve this objective, a survey was conducted among 112 project management (PM) practitioners in Ghana. The opinions from the respondents were edited, summarized and categorized by creating word queries, thus, making it easier to make deductions from them. Finally, content analysis was conducted to help establish links in the responses so as to deduce appropriate recommendations. The findings provide a set of “soft” and “hard” skills/competencies and their unique combinations for effective PM in DCs. The primary contribution of this study stems from highlighting the key competencies that project managers need to ensure effective PM in DCs, thus, helping these countries to make a more efficient use of their scarce resources.