Born at Rose Farm in rural Morgan County, Ohio, Underwood attended the public schools.

[1][2] Underwood was an unsuccessful Democratic candidate for election in 1920 to the 67th United States Congress.

He was Chairman of the Committee on Invalid Pensions for the 72nd through the 74th United States Congresses.

[1] On January 27, 1936, Underwood was nominated by President Franklin D. Roosevelt to a seat on the United States District Court for the Southern District of Ohio vacated by Judge Benson W. Hough.

Underwood served in that capacity until his death on March 8, 1972, on his farm near New Lexington and was buried nearby in Maplewood Cemetery.