Joseph Holt was born in 1807 in Breckinridge County, Kentucky. He attended St. Joseph’s College and Centre College before studying law.

In 1832, Holt established a law practice in Louisville, Kentucky, while also working as assistant editor of the Advertiser, a local newspaper. After serving for three years as the commonwealth’s attorney for the Kentucky circuit (1833-1836), he relocated to Mississippi briefly before returning to Kentucky in 1842.

Holt served as commissioner of patents (1857-1859) before being nominated by President James Buchanan to succeed the late Aaron V. Brown as postmaster general. A Democrat, Holt served as postmaster from 1859 to 1861; he then assumed the war portfolio in the Buchanan administration for the remaining three months of the Buchanan administration.

Although Holt was a southern sympathizer when he joined Buchanan’s cabinet in 1859, he had changed his views by the end of his time in the cabinet. New President Abraham Lincoln appointed Holt judge advocate general of the Army, and Holt used his position to limit the activities of southern sympathizers. Holt also adjudicated the trial of the conspirators who had assassinated President Lincoln. Holt eventually left the Democratic party for the Radical Republicans. He died in 1894.