William J. Lowry was born around 1841 in Guilford County, North Carolina, to Hugh Lowry and Ann E. Walker. His father was a farmer who owned $2,000 of real estate and $4,050 of personal property by 1860. The family enslaved at least five people. Lowry grew up and attended school in Guilford County, North Carolina. By the early 1860s, he was working as a farmer.
He enlisted in the Union army on March 3, 1862, and he mustered in as a private in Company B of the 45th North Carolina Infantry on April 9. According to his service records, he was 5 feet, 8 inches tall. The regiment took part in the Peninsula campaign, the Seven Days’ Battles, the Battle of Fredericksburg, the Battle of Chancellorsville, and the Battle of Gettysburg. He died at Gettysburg on July 2, 1863.