Costen was born on 12 February 1885 on his grandfather"s plantation, about five miles north of Sunbury, Gates County, North Carolina. He is of early English American descent, with a Methodist inheritance on both sides of his family. His great grandfather was a class leader under Bishop Francis Asbury.
Costen was the son of Samuel Isaac and Isadore (Costen) Harrell.
Costen married Amy Patton Walden 6 June 1917.
Costen earned the Bachelor of Arts degree in 1906 from Trinity College (now Duke University). He earned the Bachelor of Divinity and Master of Arts degrees in 1910 from Vanderbilt University.
He was ordained in 1911. Review Harrell served the following appointments in North Carolina: Epworth Church, Raleigh (1910-1913). Calvary Church, Durham (1913-1916), then Trinity Church, Durham (1916-1919).
And First Church, Wilson (1919-1920).
In Georgia, Review Harrell served First Church, Atlanta (1920-1925). In Virginia, Review Harrell served Epworth Church, Norfolk (1925-1929) and Monument Church, Richmond (1929-1933).
Review Harrell was then sent to West End Church in Nashville, Tennessee (1933-1944), from which he was elected to the Episcopacy.
Prior to his election to the Episcopacy, he served as a pastor.
