Shackelford was born in Richlands, North Carolina, the descendant of an early Virginia family which had settled at Shacklefords, Virginia. He enlisted in the Confederate Army at the age of 17 and rose to the rank of lieutenant during the war. In 1872, he was elected to the North Carolina House of Representatives, where he served for six years, when he was elected to the North Carolina Senate. After a single two-year term in the Senate, he was elected to the 47th United States Congress in 1880. Shackelford died in Washington, D.C. during his first and only term in office, in January 1883. He is buried in his hometown of Richlands.