Praxeology is the study of practice, i.e., human activity, primarily in the context of its rationality. The study of manager’s praxeological activity from the point of view of management theory is an important direction of modern science, since it contributes not only to improving the management effectiveness in an organization, but also to the development of new managerial concepts and techniques. In the article, the authors’ concept of praxeological managerial activity is proposed based on the analysis of existing scientific approaches to praxeology. An extended list of criteria for the manager’s praxeological activity efficiency was developed. These criteria include performance, productivity, accuracy of the decisions taken, purposefulness, reliability, innovativeness, quality, and ethics. The authors’ model of the manager’s praxeological activity includes the following elements: a subject (a manager), an object (a company, its staff and activities, etc.), motives (success, growth, profit, etc.), the goal (to ensure the effectiveness of the company’s activities), methods and tools (analysis, planning, organization, motivation, and control), process (praxeological activity), result (efficiency improvement), and reflexivity, correction and iteration. Within the framework of the model of praxeological managerial activity, the manager’s ability to influence the managed object (an organization, employees or the manager’s activities) is particularized. This influence should result in an increase in the employees’ performance, an increase in the managers’ performance, and an increase in the performance of the organization as a whole. The article will be of interest to specialists in the field of management, and corporate governance, as well as for anyone interested in the problems of effective management.