Public internal control in Brazil has been discussed by both regulatory agencies and academic research. Although regulatory bodies are proposing new structures for the internal control, recent studies have pointed out to a relatively low effectiveness in the performance of this system. This situation has been influenced by the lack of some factors that would tend to strengthen the structure, such as the existence of qualified teams and the availability of information. The present research adds the practices of an institutional logic typified as 'technical autonomy', performed by actors responsible for decision-making in the municipality, such as the mayor and the internal control's secretary, as favorable to internal control. This context enhanced the internal control legitimation towards the mentioned actors. This research adopted a declared participant observation in a Brazilian municipality. The municipality was chosen due to a management change from a predominantly political context to a predominance of a technical context. This research showed that the internal control had a greater prominence when the leadership, mayor and secretaries, presented technical characteristics. One of the reasons for this more present performance is the institutional logic of the controller and mayor, which is aligned to the technical autonomy logic also presented by the servants of the internal control department. Another factor observed was that the engagement between municipal mayor and controller made it easier for the chief executive to participate in the internal control daily activities. Thus, the technical autonomy institutional logic, observed in the local leadership, together with the active interaction between the municipal mayor and the internal controller, were seen as essential for the change in the internal control performance in this case study.