William R. Evanina (born 1967) is the former American national security official serving as Director of the United States National Counterintelligence and Security Center. As Director of the NCSC he was the head of national counterintelligence for the U.S. Government. Evanina previously served as Director of the Office of the National Counterintelligence Executive (ONCIX) before it transitioned into the NCSC. Prior to his service as National Counterintelligence Executive, he was the chief of the Counterespionage Group for the Central Intelligence Agency. He gained his initial law enforcement experience as a Special Agent for the Federal Bureau of Investigation.