We develop and test a theory of the origins and consequences of structural holes, using a theoretical framework that argues that network structures emerge from the interplay of two complementary forces: structural constraints and network opportunities. Our data comprises a co-membership network among 501 production teams in the Italian TV industry tracked over a period of 12 years. Using analysis that explicitly accounts for endogeneity, we find that structural holes spanned by teams originate from the past status and past centrality, in addition to past structural holes, but are reduced by past team cohesion and past alter content homogeneity, supporting both opportunity exploitation and structural constraint explanations. We also find independent and positive effects of both structural holes and alter content homogeneity on performance.