Determining what factors influence firm performance constitutes an essential issue in both the management and the family firm research fields. This article, building on the resource-based view perspective, develops a mediation model that involves a unique intervening mechanism, namely, technological innovation efficiency (TI efficiency), with the potential to explain the inconsistencies found in prior work on the ways through which family involvement in management affects performance outcomes. Regression analyses utilizing a longitudinal sample of 1,118 Spanish private firms largely support the hypothesized mediating relationship, revealing that TI efficiency leads to richer firm performance in family firms with active family involvement in management. Overall, our findings help elucidate the black box of performance outcomes within family firms and make several contributions to theory and practice.