Kirstjen Nielsen is the sixth Secretary of the Department of Homeland Security. During her career, she has held many public and private sector roles. Nielsen is a former White House Principal Deputy Chief of Staff to President Donald Trump as well as Chief of Staff to John F. Kelly during his term as Secretary of Homeland Security. During the Bush administration she served as Special Assistant to the President for Homeland Security and Senior Director for Prevention, Preparedness, and Response on the White House Homeland Security Council. She has also held positions at the Transportation Security Agency and the US Senate. She graduated from the Georgetown University School of Foreign Service with a bachelor of science in foreign service and from the University of Virginia School of Law with a juris doctor.