The applied ecological discipline of classical biological control (CBC) has a long history, bolstered by some spectacular successes in the management of pest insect and plant species. A major poster child of CBC is the control of prickly pear (Opuntia spp.) in Australia by the moth Cactoblastis cactorum. In this article we investigate the idiosyncrasies of this CBC program and relate it to contemporary CBC, highlighting the intensive rearing and spatially extensive distribution effort critical to the rapid success of this project. We also emphasize the importance of the sociopolitical and economic context of the Opuntia CBC program and its role in its success. We use these historical clarifications to temper the expectations of equivalent successes in future CBC projects. Cactoblastis cactorum has recently invaded North America, and its threat to native cacti is of concern. We examine the global use of this moth as a biocontrol agent to clarify the nature of the hazard that it may pose as an invader in North and Central America.