This study examines the structural relationship among key factors influencing student satisfaction and achievement in online learning. A structural model was developed by considering course structure, student–student interaction, instructor presence, student engagement, student satisfaction and achievement as key factors. In order to verify the effectiveness of the developed structural model, we utilized the survey data collected from a total of 250 students enrolled in two asynchronous online courses offered at Kyung Hee University in Korea in the fall semester of 2020. Then, the collected survey data were analyzed using the structural equation model. The verification of the statistical analysis results indicates that the course structure has a more significant effect on the student satisfaction and achievement than the other key factors such as the student–student interaction, instructor presence and student engagement. It also reveals that the student engagement affects only the student satisfaction and has a mediated effect between student–student interaction and student satisfaction.