Professor Leiter is a Professor of Law and the Director of the Program on Environmental and Energy Law at American University's Washington College of Law. She teaches environmental law, administrative law, and torts, and her research interests include administrative law and process, and domestic environmental law and policy. From August 2015 – January 2017, Leiter served as a Deputy Assistant Secretary for Land and Minerals at the U.S. Department of the Interior, advancing Department priorities related to oil and gas and renewable energy development on public lands both on- and offshore. Before joining the WCL faculty in the fall of 2011, Professor Leiter was an associate professor at Catholic University’s Columbus School of Law. Prior to that, she was a Beagle/HLS fellow at the Natural Resources Defense Council, where she developed and pursued federal appeals court challenges to EPA rules governing industrial air pollution.

Professor Leiter clerked for Judge Nancy Gertner of the Federal District Court for the District of Massachusetts; for Judge David Tatel of the U.S. Court of Appeals for the D.C. Circuit; and for Supreme Court Justice John Paul Stevens. She is admitted to practice before the District of Columbia, the States of Colorado and Massachusetts, and the U.S. Supreme Court.