Social media have become pervasive communication tools, creating connections and opportunities for customer engagement. They have redefined simple dyadic interactions between customers and marketers, transforming them into more complex interactions between multiple groups of actors, including customers, organisations, stakeholders, and non-customers. In recognition of the remodelling of customer engagement, scholars have called for additional research addressing the role of engagement in multi-actor ecosystems. Our study seeks to address this gap by advancing the understanding of the process of customer engagement on social media and proposing an empirically grounded framework with appropriate measures to assess customer engagement. Thirty-two interviews were conducted to explore the process of establishing and maintaining customer engagement on social media from the perspectives of social media marketing practitioners and users. This study proposes a dynamic framework addressing four distinct levels of customer engagement on social media, in addition to identifying appropriate measurements for each level.