In 2005 the EU launched the EU Emission Trading Scheme (now System). It was a bold and radical policy designed to both provide global leadership and commitment to the Kyoto Protocol – specifically to curb the EU’s greenhouse gas emissions from energy production and heavy industry. There followed several years of fairly serious teething problems including collapses in prices, technical problems with registry systems, implementation delays, multi-billion euro fraud, phishing scandals and a huge overhang of surplus emissions which threatened the existence of the system. Yet, 15 years later the system has been reformed, the price is holding high, with evidence of companies shifting out of fossil fuel-based technologies to cut their emissions. Importantly, it is being replicated and used as a model in markets around the world, including California, China, Mexico, South Korea and Ukraine. In this sense, the EU ETS has been an example of public policy based entrepreneurial leadership – a risky policy measure (drawn from experience of the US SOX and NOX markets) 10 to 15 years ahead of other major regions of the world. This chapter reviews the genesis and development of the EU ETS and identifies styles of leadership required and exhibited at each stage of its development, including how the bureaucratic environment, the appetite for acceleration in the climate change arena and individuals working within the EC at the time created the ‘perfect storm’ for ETS to be developed. It draws on existing theories of leadership to evaluate the extent of political and influential behaviour employed and examines the outcome for the EU and its member states.