Preston, the grandson of Col. William Preston the namesake of Prestonville, Kentucky was born Louisville, Kentucky. Francis Preston was his uncle. His sister Henrietta married Albert S. Johnston in 1829. He pursued preparatory studies and graduated from St. Joseph's College in Kentucky. He attended Yale College in 1835 and graduated from the law department of Harvard University in 1838. After graduation from Harvard, Preston was admitted to the bar and commenced practice in Louisville in 1839. William Preston died in Louisville and was interred in Cave Hill Cemetery in Louisville.