Principal academic supervision is an activity of coaching and observing and evaluating teacher performance in the teaching and learning process. This study aimed to determine the academic supervision activities carried out by the Principal of Yamisa Senior High School Soreang in improving teacher performance. This study used a qualitative approach involving school principals and teachers. The data were collected through observation, interviews and case studies. The data were analyzed using a descriptive qualitative method by describing or disclosing the characteristics of the elements which are the focus of the research. The results showed that academic supervision at Yamisa Senior High School Soreang had been going well in accordance with existing regulations, including class visits, class observations, inter-visit, private conversations at teacher meetings and workshops. Supervision of the school principal in the form of direct visits to class was conducted  by the principal routinely twice a year. In this supervision the principal enters the class directly and participated in the teaching and learning process without notifying the teacher to be supervised. The results of the supervision conducted by the Principal of Yamisa Senior High School Soreang. School produced very satisfying results, especially the teacher's performance which was better than before. The results above were also one of the supporting factors for achieving educational goals at Yamisa Senior High School Soreang