Pierce appointed Alabama lawyer and politician John A. Campbell, considered one of the finest advocates of his day. Originally from Georgia, Campbell graduated college at age fourteen and became a lawyer at the age of eighteen. Pierce nominated Campbell for a seat on the Supreme Court on the advice of several sitting justices.

Though he personally disfavored secession, Campbell resigned from the Court in 1861 after his home state of Alabama seceded from the Union. He joined the Confederate government as assistant secretary of war. He was in charge of enlisting men to fight in the war. After the war, Campbell was imprisoned for four months in Fort Pulaski, Georgia. President Andrew Johnson ordered his release, but Campbell was destitute upon his release. Campbell traveled to New Orleans and rebounded by establishing a very successful law practice. He argued a number of times before the U.S. Supreme Court, in such well known cases as the Slaughterhouse Cases (1873) and Ketchum v. Duncan (1877).