W.A. Percy and Judge Richard L. Dixon were the firm’s founders at the time the American Civil War was beginning. Shortly after the war ended, a notable case tried by W.A. Percy was his successful defense of the legendary Holt Collier who was charged with the murder of a federal officer. Collier, formerly a slave who became a soldier in the Confederate Army, was tried by a military court martial at Vicksburg, Mississippi in 1867. Percy’s advocacy secured a defense verdict for his client. Collier later became famous for guiding President Theodore Roosevelt on the 1902 “Teddy Bear” hunt in Mississippi.

W.A. Percy continued practicing law with Judge William Yerger in Greenville into the late nineteenth century, having been joined by his son, LeRoy Percy, and others. LeRoy Percy, in addition to practicing law, served as a United States Senator representing Mississippi. LeRoy Percy’s son, William Alexander Percy, who had served in France as an Army officer in World War I, also joined his father’s firm. Both Percys campaigned extensively and publicly against Ku Klux Klan activity in Washington County during the early twentieth century. William Alexander Percy was also a writer, well known for his book, Lanterns on the Levee, and various works of poetry.

After his father’s death, William Alexander Percy and Hazlewood Farish named the firm Percy & Farish. Following William Alexander Percy’s death, the firm became Farish & Keady in 1940 with the addition of William C. Keady, who quickly earned a reputation as an able trial lawyer. In 1957 the firm added Roy D. Campbell, Jr., and in 1962, Fred C. DeLong, Jr., and the firm’s name became Keady, Campbell & Delong. The three partners were well known, not only for their courtroom skills but also for their representation of individuals and business interests in matters other than litigation. In 1968, William C. Keady was confirmed as a United States District Judge for the Northern District of Mississippi where he served with distinction during a time when Mississippi dealt with major public issues including the ensuring of civil rights for all citizens and prison and education reform.

Following Judge Keady’s appointment to the Federal bench the firm continued under the leadership of Roy Campbell, Jr. and Fred DeLong, Jr. until the 1990's. The firm grew in recent times with the addition of several of the current partners. In January 2004, the firm’s name became Campbell DeLong, LLP. A framed collection of letterheads documenting Campbell DeLong’s history is on display in its office lobby.