This study qualitatively explores eight cases of best practice cities that are leading the way towards deep decarbonization. Local governments and stakeholders are developing short-term strategies and long-term pathways towards deep decarbonization at the local level but are struggling to determine effective actions. In this article, we examine cities pursuing deep decarbonization to provide insights into the strategies and governance structures that eight leading local governments are using to develop and implement deep decarbonization plans. The cases are in Canada (Bridgewater, Guelph, Vancouver and Toronto), the USA (Park City and New York City), Finland (Lahti), and Norway (Oslo) and range from very small (8.4 thousand people) to very large (9.6 million people). For each city, their implementation strategies are detailed under four categories: engagement; green economy; policy tools; and financial tools. Governance mechanisms and modes are explained regarding coordination; oversight and reporting; communication; multi-level integration; cross-sector collaboration; funding, and mode. While a number of these approaches and tools have been identified in previous research and grey literature, the findings show that leading local government plans continue to develop innovative strategies on their own and also share their successes with other communities through transnational networks. The cases examined in this study are moving beyond the incremental approach to mitigating greenhouse gases and are innovating to find applied methods for achieving transformative change. The findings from this study are useful for practitioners and academics working on climate mitigation, strategy implementation, cross-sector partnerships, and sustainable cities.