Emerson returned with Scott and Scott´s family to St. Louis in 1842. Emerson died in 1843. In 1846, the Scotts sued for their freedom, but the state court ruled against them. They refiled their suit, and in 1850 a jury ruled that they were free, based upon their prior residence in free states. This decision was overturned by the Missouri Supreme Court in 1852. In 1853, the Scotts sued for their freedom in federal court. They lost, but appealed to the Supreme Court of the United States. In the 1857 Scott v. Sanford decision, the predominantly southern Supreme Court ruled that Scott´s residence in a free state did not give him his freedom. The court also ruled the Missouri Compromise of 1820 unconstitutional and declared that African-Americans could not be citizens of the United States.

After the decision, Mrs. Emerson returned the Scotts to the Blow family, who granted them their freedom. Dred Scott died of tuberculosis in 1858, and is buried in Calvary Cemetery.