William Rufus DeVane King was born in Sampson County, North Carolina, the second son of William King and Margaret DeVane. His family was large, wealthy and well-connected. His father, a wealthy planter and justice of the peace, had fought in the Revolutionary War, served as a delegate in the state convention called to ratify the U.S. Constitution, and was an occasional member of the North Carolina state assembly. At the time of his son's birth, he owned more than two dozen slaves.
When he returned to the United States in 1818, King joined the westward migration to the Deep South, purchasing property at what would later be known as King's Bend on the Alabama River in Dallas County, Alabama. He developed a large cotton plantation based on slave labor, calling the property Chestnut Hill. King and his relatives together formed one of the largest slaveholding families in the state, collectively owning as many as 500 slaves.
I am now solitary and alone, having no companion in the house with me. I have gone a wooing to several gentlemen, but have not succeeded with any one of them. I feel that it is not good for man to be alone; and should not be astonished to find myself married to some old maid who can nurse me when I am sick, provide good dinners for me when I am well, and not expect from me any very ardent or romantic affection.
As the regional positions hardened in the tumultuous early months of 1850, King lamented the "banefull spirit of party" that in dividing the South encouraged northern extremists. In April, King's seniority and moderate views earned him a place as one of two southern Democratic representatives on the Senate's Select Committee of Thirteen, appointed to review Henry Clay's compromise resolutions regarding territories and slavery. With a majority of the committee's members, he agreed that slavery was a "rightful" subject for legislative attention, but only in the legislatures of states and not of territories. Thus, King took the view of southern conservatives that the Constitution protected owners in their control of slave property until a territory became a state. At home, he met bitter opposition from a faction of "Southern Rights" secessionists who argued that his voting record better reflected the interests of Massachusetts, but an equally large group of supporters praised his support for compromise, union, and peace. He counseled patience, optimistically expecting the North to respect southern rights, but warning that if that section's actions jeopardized those rights—both constitutional and material—all southern men should "hurl defiance at the fanatical crew, and unitedly determine to defend their rights at every hazard and every sacrifice."
King was elected Vice President of the United States on the Democratic ticket with Franklin Pierce in 1852. King served in the Senate until resigning on December 20, 1852, due to poor health (he was found to have tuberculosis).