A virtual team is a geographically dispersed organizational form that maintains the fundamental characteristics of a team structure while relying on electronic connections. This study aims to (1) examine the effects of knowledge networks that team members maintain both within and outside the group on team performance in a virtual team context, (2) empirically investigate how the level of IT utilization moderates the effect of knowledge networks on team performance, and (3) provide implications for knowledge network construction and IT utilization strategies for the effective operation of virtual teams. First, drawing on social network theory, a theoretical framework combining internal cohesion and external brokerage of knowledge networks was developed, and social network analysis was conducted on 172 individuals and 42 virtual teams. The analysis revealed that a significant linear relationship exists between internal cohesion of knowledge networks (network density) and virtual team performance. In contrast, external brokerage of knowledge networks (structural holes) showed effects on team performance that varied depending on the team-level IT utilization. This study contributes by applying traditional social network theory to virtual teams, thereby offering a new perspective on effective knowledge network construction for virtual teams.