Societies seeking sustainability are transitioning from fossil fuels to clean, renewable energy sources to mitigate dangerous climate change. Energy transitions involve ethically controversial decisions that affect current and future generations’ well-being. As energy systems in the United States transition towards renewable energy, American Indian reservations with abundant energy sources are some of the most significantly impacted communities. Strikingly, energy ethicists have not yet developed a systematic approach for prescribing ethical action within the context of energy decisions. This dissertation reinvents energy ethics as a distinct sub-discipline of applied ethics, integrating virtue ethics, deontology, and consequentialism with Sioux, Navajo, and Hopi ethical perspectives. On this new account, applied energy ethics is the analysis of questions of right and wrong using a framework for prescribing action and proper policies within private and public energy decisions. To demonstrate the usefulness of applied energy ethics, this dissertation analyzes two case studies situated on American Indian reservations: the Dakota Access Pipeline and the Navajo Generating Station.