Invasive alien species are among the major drivers of biodiversity loss, being destructive to native ecosystems, and human economy and well-being. Despite their severe negative impact, tracking the paths of biological invasions and distribution dynamics of invasive species, as well as assessing the scope and character of their interactions with resident species and ecosystems, can be difficult. An interesting case is the naturalization of the American mink in Iceland, with subsequent intensive culling and accurate registration of the number of mink killed by year and area, providing information on mink’s distributional history. Additionally, the Icelandic ecosystem is relatively simple compared to other areas within the non-native range of the American mink. The species was introduced to Iceland in 1931 for commercial fur farming. Escapees spread and multiplied in the following decades. A bounty system for culling was established early, but was unable to halt population growth and the spread of the species. Hunting statistics seem to reflect actual changes in population size and show that population density kept on increasing for three decades after the mink had colonised all suitable habitats. After 2003, the numbers show a rapid > 60% decrease, probably at least in part caused by climate change influencing the marine food web. The American mink seems to have had a negative impact on some bird and freshwater fish populations. The case of the invasive American mink in Iceland improves our understanding of biological invasions, and aids in organizing eradication programmes or control of the species.