We highlight the emerging role of technology transfer offices as institutional entrepreneurs involved in building legitimacy for novel technologies. To illustrate this role, we carry out an in-depth study of the Wisconsin Alumni Research Foundation's (WARF) initiatives to support the emergence of human embryonic stem cell (hESC) technology. Our narrative account reveals that WARF took on three sub-roles; that of protector, propagator and influencer of the nascent technology. We highlight how the dual missions of technology transfer offices (TTOs), i.e., their private and societal interests, can influence how they engage in these roles, which in turn can impact the trajectory of the technology. The implications of these findings for the literature on technology transfer, institutional entrepreneurship, and the emergence and evolution of novel technologies are discussed.