In formal inter‐firm networks backed with significant financial support by policy‐makers, network boards are typically established to monitor network activities and to manage the tension between organizational and collective interests. This approach to network governance, however, builds mainly upon agency logic. We integrate agency with embeddedness theory to offer insights into the effectiveness of monitoring as a governance mechanism as networks mature and member firms become embedded. The analyses focus on two issues: (1) how network board characteristics typically associated with monitoring – board independence, board size and board compensation – influence network performance; and (2) how these effects are moderated by network age. The model is tested with longitudinal data on 53 government‐supported networks. In addition to the direct effects of board characteristics, network board size and board compensation have a stronger positive impact on network performance in younger networks than in more mature networks. This study provides insight into why the instituting of boards may prove successful for network‐level performance in newly formed government‐supported networks, but also explains why the positive effects from network board monitoring may diminish as networks grow older.