John C. Calhoun was a prominent U.S. statesman and spokesman for the slave-plantation system of the antebellum South. A candidate for the presidency in 1824, Calhoun was the object of bitter partisan attacks from other contenders. Dropping out of the race, he settled for the vice presidency and was twice elected to that position.

Adams installed a billiards table in the White House shortly after becoming president. He wrote in his diary at the end of May 1825 that most of his evenings were "wasted in idleness or at the billiard-table." The new addition quickly became a subject of controversy, however, when Adams accidentally presented the government with a bill for the billiard table ($50), the new cloth and repair work ($43.44), cues ($5), and billiard balls ($6) (in reality he had paid for the items himself). Nevertheless, political enemies seized on the purchase, charging that the pool table symbolized Adams's aristocratic taste and promoted gambling.

The presidential election of 1828 featured one of the dirtiest campaigns in American history. The Jacksonian press portrayed Adams as an out-of-touch elitist and spread a rumor that, as ambassador, Adams offered an American girl to the Russian czar for sexual favors. On the other side, pro-Adams newspapers attacked the reputation of Andrew Jackson's wife, Rachel, who had run away from her previous husband to marry Jackson. "Ought a convicted adultress and her paramour husband be placed in the highest offices of this free and Christian land?" asked a Cincinnati newspaper. In the end, Adams' own Vice President, John C. Calhoun, joined Jackson's ticket, and Jackson won 178 of the 261 electoral votes and just under 56 percent of the popular vote.

John Quincy Adams' eldest son, George Washington Adams, disappeared on April 30, 1829, while on board the steamship Benjamin Franklin in Long Island Sound during passage from Boston to Washington, D.C. He was last seen at about 2 A.M., and his hat and cloak were found on deck, leading to the conclusion that he had intentionally jumped. His body washed ashore on June 10. An alcoholic, Adams had left notes hinting that he intended to kill himself. He had appeared to be delusional while on the ship, asking the captain to return to shore and declaring that the other passengers were conspiring against him.

Rather than retiring from public service, Adams won election to the U.S. House of Representatives, where he would serve from 1831 to his death in 1848. He joined the Anti-Masonic Party in the early 1830s before becoming a member of the Whig Party, which united those opposed to President Jackson. During his time in Congress, Adams became increasingly critical of slavery and of the Southern leaders whom he believed controlled the Democratic Party. He was particularly opposed to the annexation of Texas and the Mexican-American War, which he saw as a war to extend slavery.

In 1841, at the request of Lewis Tappan and Ellis Gray Loring, Adams joined the case of United States v. The Amistad. Adams went before the Supreme Court on behalf of African slaves who had revolted and seized the Spanish ship Amistad. Adams appeared on February 24, 1841, and spoke for four hours. His argument succeeded: the Court ruled that the Africans were free and they returned to their homes.

In his Inaugural Address on March 4, 1825, Adams said, "The will of the people is the source and the happiness of the people the end of all legitimate government upon earth.