Agricultural innovation is a top priority on the global sustainable development agenda to solve food insecurity, land degradation, climate-change issues, poverty, and unemployment. This paper aims to identify systemic problems and socio-technical transition factors that hinder the development, dissemination, and utilization of improved maize varieties in Ethiopia. Primary data were gathered through structured and semi-structured interview schedules, and then analyzed thematically. Results show that systemic failures such as the absence of key actors, institutional problems, lack of interaction between actors, and inadequate infrastructure are the major hindrances to the systems functioning. Three functions, including entrepreneurship, knowledge development, and creating legitimacy, were found to be weaker than others in the case of improved maize varieties released by Pioneer Hi-Bred Seeds Ethiopia Plc. However, these functions were stronger in the case of improved maize seed varieties released by public research centres. Knowledge dissemination and resource mobilization were the stronger functions of Pioneer Hi-Bred Seeds Ethiopia Plc., which were found to be weak in the public research centres. The result also shows that policies and governance affected the sustainable development of improved maize varieties released by Pioneer Hi-Bred Seeds Ethiopia Plc. Promoting knowledge development and resource mobilization within networks of policymakers, the public sector, and local and foreign private sectors, and a regulation on breeders’ rights to encourage the involvement of private companies in the sector are recommended to enable the innovation system to function sustainably.