We examine the interplay between identity ambiguity and praxis mastery in innovation processes within the public sector. Drawing on an ethnographic study of radical reforms in ambulance services in the UK, our study makes three contributions to theory. First, we provide a unique ethnographic account of transformational learning processes resulting in very mixed outcomes. Second, we advance an emergent model to explain contradictory findings based on the elasticity of organizational identity and praxis mastery. Third we contribute to the debates around innovative behaviours, or the lack of them, in the public sector. We discuss some practical implications for innovation among public firms especially the promotion of transitional identities supported by the mastery of social and material activities in the change process.