In civil engineering and construction management programs, student collaboration is important for their skill building, but its relationship with student engagement remains elusive. This study explored this relationship by examining the structure and characteristics of student collaboration networks. The results underscore the significance of network diameter as a measure of reachability and communication efficiency--a smaller network diameter correlates with higher engagement and suggests quicker and more-efficient communication in student groups. Structural leadership is a key factor in reducing the diameter and enhancing engagement by facilitating communication and bridging structural connection holes. In this context, structural leaders (i.e., brokers or bridges) who connect disconnected students or isolates play a more crucial role than opinion leaders (i.e., influencers or hubs) who connect a larger number of students. The findings reflect the ideal dual-lead pattern observed in industry collaborations, in which a technical lead makes critical decisions and a coordination lead diffuses knowledge and information. Strategies to nurture structural leadership are proposed, including leveraging virtual collaboration such as BIM and focusing on cultivating bridge students and their coordination skills. Additionally, the study highlights the benefits of small-world networks and reveals that demographic factors have little significant influence on engagement levels.