Thomas Rust Underwood was born in Hopkinsville, Kentucky on March 3, 1891.

[1] During World War I, Underwood served in the Students Army Training Corps at the University of Kentucky.

[1] Underwood was appointed on March 19, 1951, to the United States Senate as a Democrat to fill the vacancy in the term ending January 3, 1955, caused by the death of Virgil Chapman and served from March 19, 1951, to November 4, 1952.

He sought to retain the seat in the 1952 special election but lost to John Sherman Cooper.

[1] After his stint in the Senate, Underwood went back to his editorial duties with the Lexington Herald.