William Branch Sayers was born in Canton, Mississippi, on February 22, 1843. He was the son of Dr. David Sayers and Mary (Peete) Sayers and the younger brother of Joseph D. Sayers, who later became governor of Texas. His mother died in 1847, and in 1850 the family was living in Tallahatchie County, Mississippi, but immigrated to Texas in 1851 and settled at Bastrop. Sayers attended Bastrop Military Institute and studied law.
In September 1861, following the outbreak of the Civil War, Sayers volunteered for service in the Confederate Army and traveled to Houston where he enlisted in the Eighth Texas Cavalry (also known as Terry’s Texas Rangers). He was part of the original field staff and had the rank of sergeant major. He was later promoted to adjutant by Col. Thomas Harrison and apparently eventually attained the rank of major in the Adjutant General’s Department. At some point Sayers may have also served on the inspector general’s staff. With the Eighth Texas Cavalry, Sayers saw action in the eastern theater of war and received wounds near Johnsonville, North Carolina, on March 10, 1865.
Following the war, Sayers returned to Texas and settled in Gonzales County. He studied law and in 1867 became a partner with attorney James F. Miller. On October 2, 1868, the two men established the banking firm of Miller & Sayers in Gonzales. In 1874 Sayers married Adele Lockart; the couple had at least one son. Sayers won election as a Democratic representative for District 27—comprised of Caldwell, Gonzales, and Guadalupe counties—to the House of the Thirteenth and Fourteenth Texas legislatures. He served from January 14, 1873, to April 18, 1876. During this time he was a member of many legislative committees and chaired the Constitutional Amendments Committee and State Affairs Committee during the Fourteenth Texas Legislature. W. B. Sayers died in 1898 and was buried in Gonzales Masonic Cemetery.