Post graduation he moved to Liberty, Virginia (in Bedford County) where he taught school to support himself while he studied law. William was admitted to the bar in 1851 and began practicing law in Wytheville, Virginia as well as editing a newspaper of which he was part owner. He had been boarding with a local family near Liberty and in 1852 he married their daughter, Emma Wigginton. The couple would have seven children. William joined the local masonic lodge as well as the local militia unit, the Wytheville Grays, and was elected Lieutenant. It was he who led the unit to the execution of John Brown at Harper's Ferry in 1859. William was a slave owner with 5 slaves in 1860.
Upon Virginia's vote to succeed on 17 Apr 1861, William joined A Company 4th Virginia Infantry as a Lieutenant and was promoted to Captain soon after then moving to a staff position. He was promoted to Colonel in February 1864 and then to Brigadier General on 20 May 1864. On the next day he took command of a Brigade formed from remnants of several units including the Stonewall Brigade, the 1st Virginia Brigade. BG Terry had been wounded several times and was home recovering from wounds when Lee surrendered at Appomattox, Virginia. BG Terry attempted to join General Johnston but returned home upon learning of his surrender.
After the war William resumed his law practice in Wytheville. After he received his pardon he was elected to the House of Representative in 1870, served until 1873 having lost a reelection bid but was again elected in 1874. He again lost an attempted reelection in 1876 and returned to his law practice. He was a delegate at the Democrat National Convention of 1880.
BG Terry drowned when returning home from Grayson County Courthouse when he attempted to cross Reed Creek near Wytheville on 5 Sep 1888.
BG Terry is buried in East End Cemetery in Wytheville, Virginia.
Brother, Colonel John Fletcher Terry, commanded the 37th Virginia Infantry.
Note: this memorial was published on the 100th anniversary of his death.