Who succeeded Lincoln as president?

Andrew Johnson was Abraham Lincoln's vice president. When Lincoln, a Republican, was assassinated, Johnson, a Democrat, succeeded him to become the President of the United States during the Reconstruction period shortly after the American Civil War.

Johnson did not successfully lead the Reconstruction movement. Unfortunately for the South, Johnson’s attitude about Reconstruction maintained it as a state matter and not federal, unlike many of his Republican contemporaries.

"Johnson rose from poverty to a political career in state politics in Tennessee, which he represented in the U.S. Congress and where he was governor. Johnson championed Tennessee’s small white farmers and made enemies of the state’s large slaveowning planters. Staunchly Unionist, he was the only senator from a seceding state to remain in the Senate, and he served as Tennessee’s military governor during the war. His vice presidency, Republicans hoped, would gain support for the party in the South. But Johnson lacked Lincoln’s political acumen and ability to compromise. Johnson also defended states’ rights; he argued that since secession was illegal, southern states never actually left the Union or gave up their right to govern their own affairs. And Johnson, while supporting emancipation, was deeply racist, and did not believe blacks had a role to play in Reconstruction." - Foner, Eric. Give Me Liberty! An American History Fourth Edition. PowerPoint Chapter 15, 2015.