Several countries have been developing teaching standards for the purpose of providing recognition and more attractive career pathways to teachers who attain these standards. These initiatives aim to lift the status of teaching as a profession and to provide stronger incentives for professional learning. This article describes the work of a project at the Australian Council for Educational Research, the ACER Portfolio Project, designed to develop methods whereby teachers can demonstrate how their practice meets the Australian Professional Standards for Teachers at the ‘Highly Accomplished’ level and test them in schools for their validity and feasibility. The article describes how the Project developed an assessment framework that provided a representative sample of evidence about a teacher's practice covering the Standards, trialed portfolio tasks in schools with volunteer teachers and tested whether it was possible to train other teachers to assess their portfolio entries reliably and set standards for highly‐accomplished teaching.