US Congressman, US Senator, Governor of Maine, and 15th US Vice President. The son of a farmer, he received his education at local schools and the Hebron Academy in Hebron, Maine. From 1827 to 1830 he published the Oxford Jeffersonian newspaper in partnership with future US Postmaster General Horatio King. He then studied law and was admitted to the bar in 1833 and established a law practice in Hampden, Maine. In 1835 he entered politics when he was elected to the Maine House of Representatives. He was then elected to the US House of Representatives as a Democrat from Maine's 6th congressional district, serving two terms from March 1843 until March 1847. The following year, he was elected to the US Senate, filling the vacancy when Wyman Moor accepted a political appointment from President James Buchanan, and served in that position until January 1857. In 1856 he joined the newly formed Republican Party and in January 1857 was elected as Maine's 25th Governor but served only for a month when he resigned and returned to the US Senate for a second term, until January 1861. In 1860 he was nominated by the Republican Party as Abraham Lincoln's vice-presidential running mate, and they were victorious in the general election. He had little influence in the Lincoln administration, although he strongly supported the Emancipation Proclamation and the arming of Black Americans. During the American Civil War, he was a member of a Maine militia unit, and when it was activated in the summer of 1864, he served in the lower ranks and was mustered out after 60 days. When President Lincoln ran for a second term, he was passed over for re-election in favor of Andrew Johnson, the US military governor of Tennessee. He then returned to the US Senate, serving for two additional terms from March 1869 until March 1881. In June 1881 President James Garfield named him US Minister to Spain, and he served in that position from December 1881 until October 1882. He then returned to the US and retired from public life and died at the age of 81. Two of his sons, Cyrus Hamlin and Charles Hamblin, became brigadier generals in the Union Army during the American Civil War.