While there is evidence to indicate that social media use (SMU) has various effects on student learning and academic performance, relevant studies are still scarce while the findings are notably inconsistent. This study seeks to answer one key question: what are the mechanisms through which SMU affects student learning and academic performance? Drawing on the principles of connectivism, a research model is developed and empirically tested based on the analysis of 256 responses. The finding indicates an indirect relationship between SMU and student academic performance, intervened by student collaborative learning, student-instructor interaction, and academic distraction. This finding provides empirical evidence to support the principles of connectivism; and helps extend the scope of research on SMU and its effect on student learning and academic performance.