As Special Envoy for Guantanamo Closure from July 2015 to January 2017, Wolosky served as chief U.S. diplomat in connection with Barack Obama's efforts to close the Guantanamo Bay detention camp. Among other responsibilities, he led the Obama Administration's final diplomatic efforts to reduce the detainee population before the end of Obama's term, by transferring detainees who had been unanimously approved for transfer by the United States Secretary of Defense, State, Attorney General, Secretary of Homeland Security, Chairman of the Joint Chiefs of Staff, and Director of National Intelligence.