A native of Cornwall, Vermont, Foot began working on local farms at age nine, helping support his family after the death of his father.

Foot served in the United States House of Representatives from 1843 to 1847 and was noted for his opposition to the Mexican–American War and the extension of slavery.

In 1850 Foot was elected to the United States Senate; he became a Republican when the party was founded, and won reelection in 1856 and 1862.

Foot served as President pro tempore of the United States Senate during the American Civil War, and was a strong advocate for the Union.

He headed the Joint Congressional Committee on Public Buildings and Grounds beginning in 1861, and which included supervising completion of the United States Capitol's construction.

[1] He was the son of Dr. Solomon and Betsey Crossett Foot,[1] and his family lived across the road from William Slade.

[2]: 244  Foot's father died when he was nine years old, and he worked on local farms to help support his family.

[10] Returned to the Vermont House of Representatives, Foot was again chosen to serve as Speaker, holding the post from 1847 to 1848.

[14][15] Abbott Lawrence of Massachusetts, who had worked diligently to obtain the Presidential nomination for Zachary Taylor, expected to be the Vice Presidential nominee, counting on the support of Thurlow Weed of New York and the southern delegates who had backed Taylor.

[14][15] Recognizing that the Whigs would likely collapse if Lawrence was nominated and northern delegates left the party, Foot agreed to support Fillmore.

[17] In early 1861 Foot met the Vermont delegates to the Peace Conference which attempted to prevent the start of the American Civil War.

[18] At this meeting, he shared with them his view that the conference was a sham by secessionists who hoped to obtain additional time to plan for the withdrawal of their states from the Union.