[1] After his marriage, Hammond was elected to the United States House of Representatives as a member of the Nullifier Party, serving from 1835 until his resignation the following year due to ill health.

After spending two years in Europe, Hammond returned to South Carolina and engaged in agricultural pursuits; managing his extensive holdings took much of his time.

Hammond died on November 13, 1864 (two days before his fifty-seventh birthday), at what is now the Redcliffe Plantation State Historic Site in Beech Island, South Carolina.

[4] He popularized the phrase that "Cotton is King" in his March 4, 1858, speech to the U.S. Senate, saying: "In all social systems, there must be a class to do the menial duties, to perform the drudgery of life...It constitutes the very mudsill of society."

[6][7] Hammond and Simms were part of a "sacred circle" of intellectuals, including Edmund Ruffin, Nathaniel Beverley Tucker, and George Frederick Holmes, who promoted reformation in the South in various forms.

When the South Carolina government requisitioned 16 of the people Hammond enslaved to improve fortifications for Charleston, he refused, calling it "wrong every way and odious."

[11] Hammond's Secret and Sacred diaries[12] (not published until 1988) described, without embarrassment, his sexual abuse[1][13] over two years of four teenage nieces, daughters of his sister-in-law Ann Fitzsimmons and her husband Wade Hampton II.

[1] Such behavior was rampant among white men of power at the time; their mixed-race children were born into slavery and remained there unless the fathers took action to free them.

The letters, held among the Hammond Papers at the University of South Carolina, were first published by researcher Martin Duberman in 1981; they are notable as rare documentary evidence of same-sex relationships in the antebellum United States.

Although many of these segregation academies are now defunct, Hammond School continued to develop; after the 1970s, it expanded its admission policy, as federal law mandated, to be non-discriminatory.