Born at Lime Branch, Georgia, Blackmon moved with his parents to Calhoun County, Alabama, in 1883.

He served as chairman of the congressional committee for the fourth Alabama district from 1906 until 1910, when he resigned.

Blackmon was elected as a Democrat to the Sixty-second and to the four succeeding Congresses and served from March 4, 1911.

Blackmon had also been reelected to the Sixty-seventh Congress, but died in Bartow, Florida, on February 8, 1921.

This article incorporates public domain material from the Biographical Directory of the United States Congress