After the outbreak of the COVID-19 pandemic, schools had to continuously adapt to new pandemic-related regulations and challenges, including the ad hoc transition to remote learning. According to theories on school improvement and professionalisation, sharing knowledge and experiences with digital learning is helpful when dealing with related issues. However, no existing empirical studies analyse longitudinally how pre-pandemic experiences with sharing knowledge and digital learning impacted perceived professionalisation during the pandemic and how this relationship is mediated both by schools' strategies to improve learning and by schools' collective efficacy. For this study N = 280 school principals from Germany, Austria, and German-speaking Swiss cantons participated in two online questionnaires in 2020 and 2021. Results from the structural equation model reveal that schools' pre-pandemic experiences with knowledge sharing and digital learning are positively indirectly related to the schools' perceived professionalisation in the first and second year of the pandemic. The relationship is mediated by the schools' collective efficacy in dealing with the pandemic and the schools' use of strategies to improve teaching. The results highlight the importance of building school improvement capacity and supporting schools in digital learning to navigate through unexpected emergencies like a pandemic.