This book presents and theorises research findings into why and how school principals play a critical role in engaging parents and their school communities to enhance student learning and wellbeing. It highlights the imperative of parent engagement as evidenced by clear, consistent findings from research over the last fifty years and government reforms, policies and frameworks internationally and nationally in Australia which have been driven by the weight of this evidence. It focuses on a research project conducted from 2016 to 2017, titled 'Principal leadership for parent-school-community engagement in disadvantaged schools'. This project investigated four principals identified as successful in parent engagement based on findings of state-wide survey research of principals and presidents of parents and citizens' associations in 2014 in Queensland, Australia. This book offers theoretical and empirical evidence based on literature for the qualities successful principals in parent engagement exhibit, and the strategies they take to achieve parent and community engagement. It shows how the concept of agency as achievement can be used by educators and public policy makers to enable school leaders and teachers to adopt qualities and strategies that will engage parents in their child's learning and wellbeing, so that improved outcomes for their child and schools can result.