William M. Gwin was a native of Sumner County, born near the present town of Fountain Head, on October 9, 1805. His father, Rev. James Gwin, was a distinguished Methodist minister, who removed from North Carolina in 1790. He was a man of pronounced ability; a soldier in the War of Independence; helped to defend the frontier against the attacks of the Indians; a friend of Andrew Jackson, and his chief chaplain in his Louisiana expedition. He was in the fight at Horseshoe Bend, at Caney Fork, in November 1792; at Nickojack in 1794, and at New Orleans in 1815. When he first came to Sumner County he stopped one year at Hamilton Station. "But the wickedness of the place was such that he determined to build a cabin in the woods, and trust in God for protection, and did so accordingly, and was preserved by a most indulgent God from the merciless savages." He was a personal friend of Bishop McKendree, and for him named a son, William McKendree Gwin.

William M. Gwin, after receiving a classical, qualified himself in Gallatin for the practice of law, but abandoned it almost before beginning its practice. He then turned his attention to medicine, and in 1828 took his degree at Transylvania University. He soon afterwards removed to Clinton, Mississippi, where he soon had an extensive practice. In 1833 he retired from practice on being appointed by President Jackson Unites States Marshal for the District of Mississippi; was reappointed by VanBuren. When President Harrison went into office Dr. Gwin resigned.

Dr. Gwin was elected to Congress in 1841 and served one term, declining renomination. Previous to his election he extensively speculated in lands, and had amassed a large fortune, much of which was dissipated during his term of office. He is said to have spent $75,000 a year during his term in Congress in high living and entertaining. Tradition has it that on the occasion when General Jackson was in financial distress his friend Gwin offered to buy the Hermitage, which he proposed to present to his father for residence. In 1845 he was defeated for the United States Senate, and the same year removed to New Orleans to superintend the construction of the custom-house. He laid the fountain of the building, and proceeded with the work until General Tyler was elected President, when he resigned and set out for California, where he arrived on June 4, 1849. The establishment of a State Government was absorbing topic, and Mr. Gwin immediately entered into discussion. He was elected to the convention which met at Monterey in September to frame a Constitution.

The first Legislature met in the ensuing December, and elected John C. Fremont and William G. Gwin United States Senators. He was said to have been the first to propose a railroad to connect the Atlantic and Pacific. In 1853 he introduced a bill in the Senate appropriating $200,000 for the survey of a transcontinental railway. On January 18, 1858, he reported a bill for the construction of the Pacific road, but owing to the agitation of other questions no action was taken. He served two terms in the Senate, and closed his political career, which had been a useful one, on March 5, 1861. He acted as intermediary between Secretary Seward and the Commissioners of the Confederate Congress, to confer with the incoming administration on terms of peace and reconciliation. In 1863 Mr. Gwin was in Paris, and while there, on the invitation of the Minister of Foreign Affairs, drew up a plan for the colonization of the American Union. For two years the intrigueing continued, but nothing came of it. Dr. Gwin was a strong sympathizer of the Confederate States of the South, and rendered valuable service to the cause while in Europe. After the close of the war he returned to California and engaged in agricultural pursuits. He died in New York on September 3, 1885.