Culberson was born to Eugenia (Kimball) and David Browning Culberson in Dadeville, Alabama, but in 1856 his family moved to Texas, settling first in Gilmer and later in Jefferson. He attended Virginia Military Institute, graduating in 1874, and subsequently studying law at the University of Virginia at Charlottesville in 1876 and 1877. In 1877 he was admitted to the bar in Daingerfield, Texas, and commenced practice in Jefferson. He moved to Dallas, Texas, in 1887.

Culberson's political career began with his election to Attorney General of Texas in 1890, a position he held to 1894, when he launched his campaign for Governor. After one term as Governor, he was elected to the Senate as a Democrat on January 25, 1899. He was reelected in 1905, 1911, and again in 1916, when health problems and alcoholism prevented him from campaigning in Texas but didn't prevent his reelection. However, his health and opposition to the Ku Klux Klan finally led to the loss of his seat in the Senate in 1922 . He served as Senator from March 4, 1899 to March 3, 1923. Culberson served on the Lodge Committee investigating war crimes in the Philippine-American War.

Culberson lived in retirement until his death from pneumonia in Washington, D.C. on March 19, 1925. He is buried in East Oakwood Cemetery in Fort Worth, Texas.

This article incorporates facts obtained from the public domain Biographical Directory of the United States Congress.

Preceded by: James Stephen Hogg Governor of Texas 1895-1899 Succeeded by: Joseph D. Sayers Preceded by: Roger Q. Mills U.S. Senator (Class 1) from Texas 1899-1923 Succeeded by: Earle B. Mayfield