Professor Lazarus teaches environmental law, natural resources law, Supreme Court advocacy, and torts at Harvard Law School. He has represented the United States, state and local governments, and environmental groups in the United States Supreme Court in 40 cases and has presented oral arguments in 14 of those cases. He served as the Executive Director of the National Commission on the Deepwater Horizon Oil Spill as well as on the Biden Transition Team for the U.S. Justice Department.