Joseph Holt was an American lawyer, soldier, and politician. As a leading member of the Buchanan administration, he succeeded in convincing Buchanan to oppose the secession of the South. He returned to Kentucky and successfully battled the secessionist element thereby helping to keep Kentucky in the Union. President Abraham Lincoln appointed him the Judge Advocate General of the United States Army. He served as Lincoln's chief arbiter and enforcer of military law, and supporter of emancipation. His most famous roles came in the Lincoln assassination trials.

On April 14, 1865, Abraham Lincoln, the 16th president of the United States, was assassinated by John Wilkes Booth while attending the play Our American Cousin at Ford's Theatre in Washington, D.C. Shot in the head as he watched the play, Lincoln died of his wounds the following day at 7:22 am in the Petersen House opposite the theater. He was the first U.S. president to be assassinated. His funeral and burial were marked by an extended period of national mourning.