Born in Boscowen, New Hampshire. Married Catharine Morgan in 1826. They had seven children. Dix served in the War of 1812 and fought at Lundy's Lane. He served in the Army until 1828. Studied law and admitted to the bar in Washington, D.C. in 1824. He practiced law in Cooperstown, New York. He was appointed state adjutant general in 1830. He was secretary of state in New York 1833 to 1839.

Elected to the United States Senate and served January 27, 1845, to March 3, 1849. President of the Chicago and Rock Island Railroad and the Mississippi and Missouri Railroad 1854 to 1857. In 1860 he was appointed postmaster in New York City by President James Buchanan.

Appointed Secretary of the Treasury by President Buchanan and served January 15, 1861, to March 6, 1861. When Louisiana seceeded from the Union, Dix sent a message January 29, 1861, to the Treasury Officer in New Orleans, "If any one attempts to haul down the American flag, shoot him on the spot." This has been misquoted as "Shoot him on the spoot." The spoot is a part of the anatomy just below the Mason Dixon line.

Dix served as major general 1861 to 1865. He was considered too old for a command. He was responsible for suppression of the draft riots in New York in 1863. Dix served as minister to France 1866 to 1869. He was elected Governor of New York and served 1873 to 1875. He died in New York City.

bio: ApCAB; BDC; BDEB; DAB; Drake; NCAB 5; TCBDA; WAB; WWWA-H