Which President succeeded Abraham Lincoln?

Andrew Johnson succeeded Abraham Lincoln as President of the United States. Johnson took office on April 15, 1865, following Lincoln's assassination just days earlier. He was Lincoln's Vice President and assumed the presidency during a critical period—the immediate aftermath of the Civil War, when the nation was grappling with the issues of Reconstruction and healing.

Johnson's presidency was marked by significant challenges, including the struggle to implement a reconstruction plan that balanced leniency toward the Southern states with the need to protect the rights of newly freed slaves. His approach and policies would later lead to intense political conflict, including his impeachment by the House of Representatives, although he was acquitted by the Senate.

The other figures listed did not succeed Lincoln directly: Ulysses Grant followed Johnson in the presidency, Rutherford Hayes succeeded Grant, and James Buchanan was in office prior to Lincoln. Thus, Andrew Johnson is recognized historically as the immediate successor to Abraham Lincoln.