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.

The Judge Advocate General of the United States Army (TJAG) is the senior officer of the Judge Advocate General's Corps of the United States Army. Under Title 10 of the United States Code, the TJAG is appointed by the President of the United States with the advice and consent of the Senate. Suitable candidates are recommended by the Secretary of the Army. By statute, TJAG serves a four-year term as the legal adviser of the Secretary of the Army and of all officers and agencies of the Department of the Army; directs the members of the Judge Advocate General's Corps in the performance of their duties; and receives, revises, and has recorded the proceedings of courts of inquiry and military commissions 10 U.S.C. § 7037.