Colquitt defended the actions of the Texas Rangers who allegedly crossed into Mexico in pursuit of the body of Clemente Vergara in March 1914.

Thomas Jefferson Colquitt served in the Confederate States Army as an officer, and after the Civil War, attempted to farm using freed slaves as laborers.

[4] Eager to start over, Colquitt's family moved to Morris County, Texas, arriving in Daingerfield on January 8, 1878.

[5] Colquitt then spent one term at the Daingerfield Academy,[3] where he boarded with the family of state legislator John A. Peacock.

After leaving school, Colquitt unsuccessfully attempted to get a job as a brakeman or fireman with the East Line and Red River Railroad.

[6][7] In 1890, Colquitt campaigned in favor of the creation of the Railroad Commission of Texas and vigorously supported the election of Jim Hogg as governor.

He served as the state revenue agent for the last eight months of 1898 and wrote a report for the special tax commission that was submitted to the legislature in 1900.

"[4] In 1906, Colquitt ran for governor, but, in part due to his opposition to Prohibition, he failed to win the Democratic nomination.

"[6] Although his opponents referred to him as "Little Oscar" for his diminutive stature, Colquitt won both the primary and the general election.

[6] He was not present for the Democratic convention which nominated him for the position, as his youngest son, Oscar B. III age 4, died in Austin at roughly the same time.

[10][11] He ran for the U.S. Senate in 1916, but was defeated in the Democratic primary runoff election by incumbent Sen. Charles Allen Culberson.