Who became president after Abraham Lincoln's assassination?

Andrew Johnson became president after Abraham Lincoln's assassination because he was serving as vice president at the time of Lincoln's death in 1865. Upon Lincoln's assassination, Johnson was sworn in as the 17th president of the United States. His presidency began at a crucial and turbulent time during the Reconstruction era following the Civil War. Johnson, a Southern Democrat, faced significant challenges as he sought to implement a plan for the reintegration of the Southern states while dealing with the opposition from Congress, particularly the Radical Republicans. His policies and disagreements with Congress eventually led to his impeachment, although he was acquitted and remained in office until the end of his term.

In contrast, Ulysses S. Grant, the commanding general of the Union army, became president later, succeeding Johnson in 1869. The Radical Republicans were a faction within the Republican Party during the Civil War and Reconstruction but were not individuals who could take the presidency in that manner. Rutherford B. Hayes served as the 19th president much later, from 1877 to 1881, after the period of Johnson's presidency. Thus, the significance of Andrew Johnson's succession lies in his immediate role after Lincoln's assassination and the unique context of his administration.