Johnson won election to the U.S. House of Representatives in 1843. Like in the state congress, Johnson advocated on behalf of the poor and dispossessed. He argued for a measure that would provide for free land for farmers who had lost their land. After serving a term as governor of Tennessee, Johnson won election to the United States Senate in 1857. He pushed for the adoption of the Homestead Act, which gave up to 160 acres of undeveloped land to settlers willing to move and settle out in the Midwest and West.