Greenpeace was founded in Vancouver in the early 1970s. Initially, it was a small anti-nuclear protest group composed of Americans and Canadians, peaceniks and hippies, World War II veterans and people barely out of high school. Twenty years later, it was the world’s largest environmental NGO, with headquarters in Amsterdam, branches in over forty nations, and a regular presence at international environmental meetings throughout the world. This article will chart Greenpeace’s growth throughout its first two decades, in the process examining how the organization became influential at several levels: in local politics in places like Vancouver; at the national level in countries such as Canada, New Zealand, the USA, and Germany; and at global forums such as the International Whaling Commission and various UN-sponsored environmental meetings. It will analyze the combination of activist agency and political op-portunity structures that enabled Greenpeace to gain political influence. I argue that Greenpeace’s influence largely stemmed from its engagement with what political scientist Paul Wapner calls “world civic politics,” which in this case involves the dissemination of an ecological sensibility that indirectly influences behavior at multiple scales, from individuals, to governments, to multi-lateral organizations. Only in this way could a group with relatively limited resources hope to influence millions of individuals and powerful governments.