This article reports on the fourth stage of an evolving study to develop a systems model for embedding education for sustainability (EfS) into preservice teacher education. The fourth stage trialled the extension of the model to a comprehensive state-wide systems approach involving representatives from all eight Queensland teacher education institutions and other key policy agencies and professional associations. Support for trialling the model included regular meetings among the participating representatives and an implementation guide. This article describes the first three stages of developing and trialling the model before presenting the case study and action research methods employed, four key lessons learned from the project, and the implications of the major outcomes for teacher education policies and practices. The Queensland-wide, multi-site case study revealed processes and strategies that can enable institutional change agents to engage productively in building capacity for embedding EfS at the individual, institutional, and state levels in preservice teacher education. Collectively, the project components provide a system-wide framework that offers strategies, examples, insights, and resources that can serve as a model for other states and/or territories wishing to implement EfS in a systematic and coherent fashion. [Paper presented at the 18th AAEE Biennial Conference--Sustainability, Smart Strategies for the 21st Century.]