John Elmer Thomas, the son of a farmer, was born in Greencastle, Indiana, on 8th September, 1876. He graduated from DePaux University in 1900 and worked as a lawyer in Oklahoma City and Lawton.

A member of the Democratic Party, Thomas was elected to the 68th Congress in 1922. Over the next few years he worked closely with William Borah, Henrik Shipstead, Bronson Cutting, Lynn Frazier, Robert LaFollette Jr., Gerald Nye, Burton K. Wheeler and other progressives in the Senate.

Thomas was chairman of the Committee on Indian Affairs and served on the Committee on Agriculture and Forestry. An unsuccessful candidate for renomination in 1950, Thomas worked as a lawyer in Washington before returning to Lawton, Oklahoma, in 1957. John Elmer Thomas died on 19th September, 1965.