Mark J. Lesko is a former federal prosecutor and experienced trial lawyer who spent years directing complex legal teams and leading large institutions in the public and private sectors. Mark has personally tried more than three dozen cases, handled 25 appeals and 15 appellate oral arguments, and conducted and supervised thousands of investigations, prosecutions, and cases across criminal, civil, and regulatory practices.
Mark recently served as Acting Assistant Attorney General (AAG) for DOJ’s National Security Division. In this role, he was the DOJ’s highest-ranking national security lawyer and held one of the highest security clearances in the U.S. government. Mark oversaw nearly 400 employees who protect the nation’s security against terrorism, espionage, cybersecurity threats, and other national security threats. During his time as Acting AAG, Mark frequently briefed various congressional committees and the White House on highly sensitive matters. He led the DOJ’s counterterrorism efforts, including a particular focus on combatting cyber-based terrorism threats, and oversaw the Export Control Section, which investigates and prosecutes espionage cases, including cases involving economic espionage, theft of trade secrets, the illegal export of military and strategic commodities, and certain cyber-related activity. He also led the DOJ’s work on the Committee on Foreign Investment in the United States (CFIUS), supervised cases involving the unauthorized disclosure of classified information and the enforcement of the Foreign Agents Registration Act (FARA), and led the implementation of reforms related to surveillance authorizations under the Foreign Intelligence Surveillance Act (FISA).
Prior to this, Mark served as Acting United States Attorney for the Eastern District of New York (EDNY), where he supervised more than 175 AUSAs and was responsible for all criminal prosecutions and civil litigation on behalf of the district. Mark was a federal prosecutor for over 13 years and he held a number of other leadership positions in the EDNY, including First Assistant United States Attorney, Special Counsel to the U.S. Attorney, and Deputy Chief of the Long Island Criminal Division. Mark was also an AUSA in the District of Columbia, where he served in the homicide/major crimes section.
Mark was also the three-time elected Supervisor of the Town of Brookhaven – New York’s second-largest Town with approximately 486,000 residents – where he supervised approximately 2,000 employees and managed a $270 million budget.
Mark also previously served as Vice President for Economic Development at Hofstra University and as Executive Director of Accelerate Long Island, where he ran a regional investment fund that invested in startup technology companies. In addition, Mark was a commercial litigator at large law firms in Washington, D.C. and Pittsburgh, Pennsylvania. Mark practices out of Greenberg Traurig’s Long Island, New York City, and Washington, D.C. offices.
