Final answer:
John Wilkes Booth, a Confederate sympathizer and actor, assassinated President Abraham Lincoln at Ford's Theater on April 14, 1865.
Step-by-step explanation:
The Southern sympathizer and actor who assassinated President Lincoln was John Wilkes Booth. On April 14, 1865, while President Abraham Lincoln was attending a play at Ford's Theater, Booth carried out his plan to kill the President due to his support of the Confederacy and his opposition to the citizenship and freedoms for Black individuals. Booth's brutal act was a part of a larger conspiracy aimed at undermining the Union government.
After the assassination, Booth fled but was eventually located and killed by Union troops. The aftermath of Lincoln's assassination led to immediate national mourning and further distrust towards the South, as people speculated about broader conspiracies involving Confederate leaders.