This study investigates the role of GovTech incubators in bridging the gap between prototyping and the long-term implementation of digital innovations in the public sector. While incubators effectively foster collaboration between startups and government agencies, systemic challenges—such as scarce resources, complex procurement processes, and cultural differences—often hinder sustainable adoption. Based on a qualitative multiple case study of two German GovTech incubators, we identify critical success factors throughout the incubation process that facilitate value co-creation. However, existing models struggle to address barriers in scaling and implementation. To bridge this gap, we propose a GovTech incubator process model that extends support across the entire innovation lifecycle, focusing on tailored post-incubation strategies for compliance, scalability, and cultural alignment. This study contributes to public sector innovation research by integrating the dynamics of long-term implementation into value co-creation frameworks and providing actionable insights for sustainable GovTech innovation.