This article offers a review of research and scholarly work about why it matters that new teachers have early opportunities to engage in leadership activities despite their beginner status. It builds on a continuing strand of literature grappling with leadership work as an organisational quality, manifest in activity and practice which need not be restricted to those with formal leadership roles. If capacity building for leadership is left until later in a teacher's career, this can mean those with potential to lead may have already left the profession in search of new challenges. That early career teacher attrition continues to be a worldwide concern, suggests more could be done to address this unfortunate trend. This article takes on that challenge through a deepening of insights about essential on-the-job practice for early career teachers. The literature is presented through three themes: teachers' need for learning, teacher leadership as collective work for improved student learning, and trusting relationships, colleagues' pedagogical expertise and modelling with coaches and mentors. These themes recognise teachers' professional learning as the pathway to leadership influence which can begin on entry to teaching. The article concludes with questions to be addressed by schools in dialogue with early career teachers.