Tsosie, who is of Yaqui descent, has worked extensively with tribal governments and organizations and serves as a Supreme Court Justice for the Fort McDowell Yavapai Nation. She joined the College faculty in 1993 and has served as Executive Director of the top-ranked Indian Legal Program since 1996. She was appointed as a Willard H. Pedrick Distinguished Research Scholar in 2005 and, before that, she held the title of Lincoln Professor of Native American Law and Ethics.
She teaches in the areas of Indian law, Property, Bioethics, and Critical Race Theory, as well as seminars in International Indigenous Rights and in the College's Tribal Policy, Law, and Government Master of Laws program. She has written and published widely on doctrinal and theoretical issues related to tribal sovereignty, environmental policy and cultural rights, and is the author of many prominent articles dealing with cultural resources and cultural pluralism. Tsosie also is the co-author with Robert Clinton and Carole Goldberg of a federal Indian law casebook. Her current research deals with Native rights to genetic resources. She annually speaks at several national conferences on tribal sovereignty, self-determination, and tribal rights to environmental and cultural resources.