James K. Polk focused on a political career throughout his life. After a brief time clerking for the Tennessee Senate, he won a seat in the Tennessee House of Representatives (1823–1825). In 1825, Polk became a member of the U.S. House of Representatives and served there for fourteen years.

As a congressman, Polk became known as a huge supporter and ally of Andrew Jackson. Because of his support, Polk was given the nickname “Young Hickory” in reference to Andrew Jackson's nickname “Old Hickory.” When Jackson won the presidency, Polk became very powerful in the House. He fought for lower taxes and against the Bank of the United States, and was chosen to be speaker of the House from 1835 to 1839. He left Congress to become governor of Tennessee from 1839 until 1841.