Born in Barnwell County of distinguished ancestry, William H. Townsend received his education principally from tutors, among whom was his relative, G. Duncan Bellinger, Sr., once an Attorney General of South Carolina. He came to the Bar by reading law in the office of Judge Robert A. Aldrich of Aiken. He practiced in Beaufort with Colonel William Elliott, in Barnwell with Bellinger, Townsend and O’Barnon, and in Columbia in association with G. Duncan Bellinger, with Benjamin L. Abney and as a sole practitioner. He was Solicitor of the Second Judicial Circuit in 1898, leaving that position to become Code Commissioner and editor of the 1902 Code. He became an Assistant Attorney General in 1903 and served as Supreme Court Reporter from 1913 until 1918.
Elected Circuit Judge of the Fifth Judicial Circuit in 1918, he continued in that office until his death in 1934. He exemplified the highest traditions of the Bench, presiding with dignity and fairness, listening with courtesy and consideration, deciding with promptness and clearness, and tempering justice with mercy. He was a devout member of the Presbyterian Church, and for many years, an elder in the First Church of Columbia.