This is a partial list of notable historical figures in U.S. national politics who were members of the Ku Klux Klan before taking office. Membership of the Klan is secret. Political opponents sometimes allege that a person was a member of the Klan, or was supported at the polls by Klan members.

John Tyler Morgan was an American politician who was a brigadier general in the Confederate States Army during the American Civil War and later was elected for six terms as the U.S. Senator (1877–1907) from the state of Alabama. A prominent slaveholder before the Civil War, he became the second Grand Dragon of the Ku Klux Klan in Alabama during the Reconstruction era. Morgan and fellow Klan member Edmund W. Pettus became the ringleaders of white supremacy in Alabama and did more than anyone else in the state to overthrow Reconstruction efforts in the wake of the Civil War. When President Ulysses S. Grant dispatched U.S. Attorney General Amos Akerman to prosecute the Klan under the Enforcement Acts, Morgan was arrested and jailed.