This paper examines the effects of management functions on the performance of diverse teams working on projects in the Information Technology (IT) industry, as well as the impact of their performance on organizational sustainable performance. Grounded on organizational management and work team management specific empirical studies and literature, we clarified the content of management functions in the framework of teamwork and acknowledged manners to express the performance of teams distinguished through diversity, as well the most relevant positive effects of team results on organizational performance. On the above basis, we built the online questionnaire. The study involved 189 respondents, who work either in Romania or in the Czech Republic on IT field specific projects. Empirical results show that, individually, some management functions are connected with co-workers’ and teams’ performance, while others are not, but considered together, in interdependence with joint effects, they influence the team’s performance and the organization’s performance from the perspective of its sustainable strategic competencies.