Leopold previously served as general counsel of the Florida Department of Environment Protection. He was also an attorney at the United States Department of Justice's Environment and Natural Resources Division. Leopold's legal practice focuses on environmental law, policy, and litigation. He has represented the state and federal governments on complex environmental litigation, including "Florida v. Georgia" and "United States v. BP Exploration and Production, Inc.", which addressed the 2010 "Deepwater Horizon" oil spill in the Gulf of Mexico. Leopold also represented Florida in litigation related to the Everglades. He previously served as an environmental policy advisor for former Florida Governor Jeb Bush. He is a graduate of the University of Florida and Florida State University School of Law.