Marketisation has brought complex changes to the education sector that have become a concern both in the literature and among the public. However, few studies have empirically investigated how private school teachers' professional identities might differ from those of state school teachers. This study compares how 16 teachers in two state schools and two private schools negotiate their professional identities in County Nanqi (a pseudonym) in China. A constructivist perspective guided the choice to employ a qualitative approach in this study. The research findings suggested both common and differing teacher professional identity (TPI) characteristics among state and private school teachers and developed a typology of professional identities based on the analysis. This article focuses on the two 'positive' types of professional identities, namely, developmental and structural, to extend the existing forms of professional identity construction and discuss the comparative characteristics of teachers' work and lives in state and private schools in China. The results reveal the need for longitudinal research to further facilitate the comparative perspective and contextualisation of both 'positive' and 'negative' TPIs in diversifying school contexts.