William Ayres was born on March 8, 1823, in Pennsylvania to William Ayres. He grew up in Harrisburg, Pennsylvania, before moving to Philadelphia, Pennsylvania. He earned a living as a merchant. He married a woman named Ellen, and they had at least four children: Mary, born around 1847; Charles, born around 1852; Beecher, born around 1856; and James, born around 1859. By 1860, he owned $4,500 of real estate and $6,000 of personal property.
In early 1862, he travelled to Virginia to visit the Manassas battlefield. Confederate forces captured and imprisoned him. He was exchanged in April 1862 for Austin E. Smith. He returned to Philadelphia and resumed his work as a merchant. His wife probably died in the early 1860s, and he married Kate Watson on January 5, 1865. Their son Watson was born around 1868. By 1870, he owned $25,000 of personal property, and he employed at least three white domestic servants.
His wife probably died sometime after 1870, and he married Kate Bottorff. In the late 1800s, he reportedly became “connected with the Provident Savings Company of Philadelphia.” He died of heart disease in Philadelphia on April 14, 1898.