John Overton was born in Marksville, Louisiana, on 17th September, 1875. He graduated from the Louisiana State University at Baton Rouge in 1895. After graduating from the law department of Tulane University he was admitted to the bar in 1898.

Overton worked as a lawyer in Alexandria, Louisiana. A member of the Democratic Party, Overton, with the strong support of Huey Long, was elected to Congress in May 1931. The following year he was elected to the Senate. He was chairman of the Committee of Manufactures and served on the Committee on Commerce and Committee on Irrigation and Reclamation.

John Overton died on 14th May, 1948.