George Washington Whitmore, Unionist politician and Republican leader, son of John and Elizabeth Whitmore, was born in McMinn County, Tennessee, on August 26, 1824. He moved to Harrison County, Texas, in 1848 and was admitted to the state bar on July 1, 1850. He established a law practice and became a property holder and slaveowner during the next decade. Whitmore began his political career as a campaigner for the Whig party in the presidential election of 1852, indicating that he tended to support Unionist positions and a relatively strong and active national government. In August 1853 Whitmore won a seat in the House of Representatives of the Fifth Texas Legislature. After the demise of the Whig party during the mid-1850s, he became identified with the American (Know-Nothing) party, but he did not run for office again until 1859, when he won a seat in the Eighth Legislature as a supporter of Sam Houston. During the crucial election of 1860, Whitmore looked to the Constitutional Union Party to give voice to his Unionism. He became an alternate elector for the party in the first congressional district of Texas and campaigned for John Bell throughout East Texas. When Abraham Lincoln's victory sparked a secession movement in Harrison County, Whitmore's well-known Unionism led to a demand that he resign his seat in the state legislature. He refused and attended the special legislative session called by Governor Houston in January 1861 in an effort to forestall secession. Whitmore was one of only thirteen representatives to vote against a resolution validating the Secession Convention, and after the convention passed an ordinance of secession on February 1, he joined a handful of other Unionist leaders in signing the "Address to the People of Texas" condemning disunion.
During the Civil War Whitmore moved to Smith County, where his family from Tennessee had settled during the 1850s. He remained an outspoken Unionist, and as a result, in November 1863, Confederate authorities arrested and imprisoned him for nearly twelve months without formal charges or a trial. Part of this time was spent in Camp Ford at Tyler. Following his release in late 1864, Whitmore remained in Smith County until the war ended, after which he played a major role in Reconstruction. His first office came in August 1865 when the provisional governor of Texas, Andrew J. Hamilton, appointed him district attorney for the Ninth Judicial District. He held that position until June 1866. Congressional Reconstruction beginning in 1867 worked in Whitmore's favor both personally and politically. In August he received the appointment as register in bankruptcy for the federal district court at Tyler. He also joined the fledgling Republican party in 1867 and won a seat in the Constitutional Convention of 1868–69. He served as temporary chairman of that convention and also as a member of the influential Committee on Lawlessness and Violence in Texas. In August 1868 he was chosen as president pro tem of the so-called Radical Republican state convention. Throughout this period of political activity, he was identified with the Radical Republican faction led by Edmund J. Davis. In December 1869 Whitmore won a seat in the United States House of Representatives, representing the first congressional district of Texas. He served in the Forty-first Congress in 1870–71 but lost a disputed reelection contest to Democrat William S. Herndon in October 1871. He remained active in the Republican party after this defeat, serving on the Platform Committee at the party's 1873 state convention. But the Republicans, plagued by factionalism among moderates and radicals and unable to build a constituency among the white majority in Texas, soon became powerless. Whitmore married Harriet Bell of Harrison County in 1851. They adopted one child and reared three orphans but had no children of their own. Harriet Whitmore died in October 1875 at the age of forty. George W. Whitmore died on October 14, 1876, at Tyler.