The comparative study arose from our curiosity about why policies towards e-cigarettes were so different in the UK and Australia, two countries with a shared public health history. The US was added as a case study to see how its unique history of tobacco activism and anti-tobacco activism prefigured and influenced its e-cigarette policy. We outline the history of tobacco policy in the context of public health in each country, showing that a major change occurred after World War II, when tobacco became a key issue of public health concern. All the countries developed stances hostile to tobacco smoking and to the tobacco industry, but differences in the way this was done helped to inform their policies towards e-cigarettes, which cover a spectrum of tolerance. An important source of divergence between the three countries was a history of policy in the UK favouring a harm reduction approach to nicotine. In the US and Australia, while nicotine was used as individual therapy, it was in pursuit of a cession-only strategy.