The promotion of active transportation (AT-utilitarian trips including walking, cycling, and public transit use), represents a well-recognized opportunity for increasing physical activity. This study examines the strong AT success achieved in Helsinki, Finland (in 2013, the share of daily trips in Helsinki completed by AT was 77 per cent) from a political perspective. Helsinki represents a noteworthy example of AT success given important challenges including the region's relatively low population density, its difficult winter climate, and Finland's high driving rate. This research applied the advocacy coalition framework (ACF), a formal policy process theory from political science. Interviews were conducted with 23 AT experts in Helsinki. Document review was employed as a secondary method. Overall, the research indicates that Helsinki's success may be attributed to the long-term dominance of municipal transportation policy by a pro-AT advocacy coalition. When viewed from the perspective of health promotion, it is striking that this success is not strongly attributable to health considerations or efforts from health-related fields. Rather, the data suggest that the coalition, comprised of members from a variety of non-health fields, was most strongly motivated by a desire to protect a high degree of livability. Importantly, a number of significant historical events and background-level factors greatly facilitated success. Overall, these results suggest that health promotion advocates may have very useful allies in non-health sectors, and that awareness of the importance of political factors is likely to contribute to stronger health promotion efforts. Finally, several possibilities for related and further research are suggested.