Secret Service Director Julia Pierson prepares to testify to the House Oversight and Government Reform Committee on the White House perimeter breach at the Rayburn House Office Building on September 30, 2014 in Washington.

Secret Service Director Julia Pierson resigned Wednesday after lapses in the president's security came to light.

Joseph Clancy, who formerly served as special agent in charge of the Presidential Protective Division of the Secret Service, will be appointed interim acting director of the agency.