John Floyd was born on April 24, 1783 at Floyd Station, Kentucky, twelve days after hostile Indians killed his father. The youngest of three children, he was educated at home and in a nearby schoolhouse before entering Dickinson at age thirteen. He matriculated with the class of 1798 but was forced to withdraw for financial reasons. He rejoined the College in 1801 but after a year was obliged to withdraw permanently with a serious lung illness. He removed to Philadelphia and was placed under the care of Benjamin Rush.
This experience influenced his choice of career and he began a medical apprenticeship under Richard Ferguson of Louisville, Kentucky, after which he entered the University of Pennsylvania Medical School, graduating in April 1806. He began his practice in Lexington, Virginia and then settled in Christianburg, Montgomery County.
Floyd served with the Army as a surgeon with the rank of major in the War of 1812 and was a member of the Virginia General Assembly in 1814. He was elected to Congress in 1817 and remained in that seat for twelve years. He was a staunch proponent of the occupation of the Oregon Territory and supported Jackson's election in 1828. On January 9, 1830 he was chosen as Governor by the Virginia state legislature and was re-elected in 1831 for a three-year term. During this second term, the occurrence of the Nat Turner slave uprising caused Floyd to reevaluate his views on slavery and abolition. Nonetheless, he retained his pro slavery views and attempted to bring Henry Clay and John C. Calhoun together in a new political party to support such views. The attempt was unsuccessful and Floyd suffered a stroke in 1834 while still in office, but was able to serve out his term.
While a young medical apprentice in 1804, he had married Letitia Preston. The couple had nine children, the most famous of whom was John Buchanan Floyd, who served as Virginia governor and as a major general in the Army of Northern Virginia during the Civil War. The older John Floyd suffered a second stroke and died on August 16, 1837. He was fifty-four years old.