Biocultural co-inhabitation implies a triple ethical duty: to foster the well-being of the co-inhabitants, to respect their lifestyles, and to care for the habitats shared with them. To address this imperative of the biocultural ethic, I examine the work of American environmental philosopher Eugene C. Hargrove, who founded the journal Environmental Ethics (EE) and established a solid academic platform for the new transdisciplinary field of environmental philosophy at the end of the twentieth century. I argue that for twenty-first century environmental ethics, his pioneering work is relevant due to two fundamental attributes: his philosophical analysis of the history of ideas and his transdisciplinary approach. These attributes are vital to address the ultimate causes of the global socio-environmental crisis, which constitutes one of the greatest threats to the sustainability of life and the conservation of its biological and cultural diversity. The ultimate causes of this crisis are cultural, educational, and value based. I highlight how Hargrove uses his transdisciplinary approach rooted in the history of ideas to focus on aesthetic values. In this way, he expands the spectrum of the values of nature that should be considered in environmental policy and education. Toward this aim, he documents a broad diversity of thinkers, artists, and other citizens who have treasured nature since the dawn of Western civilization. Importantly, Hargrove emphasizes that members of different societies and ethnic groups should cultivate forms of environmental ethics rooted in the values of their own culture. In summary, he proposes that environmental ethics should be transdisciplinary, international, and intercultural in order to be effective and just. For these reasons, I argue that Hargrove’s contribution to environmental ethics and aesthetics takes on special relevance in countering pervasive processes of biocultural homogenization that are amplified by global society, and in inspiring, instead, contemporary forms of biocultural conservation.