The development of STOL (Short Take-off and Landing) aircrafts for relatively short take-off and landing naturally leads to the study of the flow field around high-lift wings, including the effects of aerodynamic high-lift devices such as leading and trailing-edge flaps. These wing configurations are known to exhibit complex flow dynamics, with areas of significant flow separations caused by strong adverse pressure gradients that negatively impact the wing aerodynamic performance. To overcome these challenges, flow control techniques can be applied to high-lift wings to significantly increase the lift coefficient and reduce flow separations by increasing flow momentum over the high-lift surfaces. In this paper, the influence of an active flow control through steady blowing over a high-lift airfoil was experimentally analyzed. The flow control actuator was applied on 75% of the airfoil chord over of the trailing-edge flap upper surface. Pressure distribution over the surface with different leading- and trailing-edge flap deflections, including high deflections, was measured in the TA-3 subsonic wind tunnel of Aeronautics and Space Institute (IAE), at Reynolds numbers of 4.27 × 105. The results demonstrated that the blowing jet had a significant impact on the pressure distribution around the airfoil and effectively prevented flow separation over the trailing-edge flap by increasing flow momentum. The blowing jet created noticeable suction peaks near the jet slot, and the magnitude of these peaks increases with higher values of the jet momentum coefficient. When combined with high flap deflections, the blowing jet caused a substantial increase in the lift coefficient. Although, it was also observed that the pressure distribution in non-active actuator regions was influenced by the blowing, emphasizing the need for comprehensive consideration of flow control implementation regarding its overall three-dimensional effects.