This article proposes an account of how two teachers’ labour federations have been reacting to austerity measures in public education. Current austerity measures have coincided with the renewal of collective agreements; thus allowing the study of how unions link bargaining stances to wider issues of service quality and accessibility. Union responses are the result of at least three influences: the institutional framework for public sector collective bargaining and worker representation, the previous orientation of members and their organisations towards social and work relations and, ongoing innovations for renewal and member engagement. We posit that union responses can contribute to renewal if they are guided by concerns to redefine union purpose, union organisation and building capacities. Under these conditions, unions are able to engage members and push forward an alternative agenda to that of the government. In doing so, they may be able to forge temporary alliances with outside stakeholders, namely parents. Analysis of union responses should consider the dialectic between union renewal effort and the opportunities and constraints of the institutional framework for public sector collective bargaining. The challenge for these two labour federations is in sustaining member engagement and activism beyond the current context of collective bargaining.