As Acting AAG of the National Security Division, Mark 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, 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 EDNY, where he supervised more than 175 AUSAs and was responsible for all criminal prosecutions and civil litigation on behalf of the district.  Among many noteworthy cases, Mark supervised the prosecution of Joaquin "El Chapo" Guzman Loera, the 1MDB Malaysian $6 billion bond fraud involving Goldman Sachs, and he was the lead prosecutor in U.S. v.  Sabhnani  (known as the "Muttontown Slave Case"). Mark was a federal prosecutor for over 13 years and he held a number of other leadership positions in the EDNY, including First Assistant U.S. Attorney, Special Counsel to the U.S. Attorney, and Deputy Chief of the Long Island Criminal Division.  Mark received the Attorney General’s Award for Distinguished Service in connection with the prosecution and trial conviction of NXIVM cult leader Keith Raniere.  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 firms in Washington, D.C. and Pittsburgh, Pennsylvania.

​

Mark is a graduate of Yale University and Georgetown University Law Center.