William Jackson Blanton was the son of Clayborn Blanton and his first wife, the former Miss Mary Dobbins. His mother was clearly identified in the 1857 Will of his maternal grandfather, Ezekial Dobbins. The elder gentleman named William and his sister, Jane, as beneficiaries and instructed that they were to receive their mother's "distributive share." When Mr. Blanton died in 1918, L.B. (Landrum Brown) Blanton, his son, identified William's mother as "Dobbins" without a first name on the Certificate of Death.

The salient dates for Mary Dobbins Blanton remain unknown. Her daughter, Jane, was born in 1835 and her son, William, in 1843. Mary Blanton was not on the 1850 Census. By then, Clayborn Blanton had married Jane "Jenny" Bridges, the daughter of Samuel and Eliza Hamrick Bridges. The 1850 Census of Spartanburg, SC enumerated:

Clayton Blanton 40
Jane Blanton 40
Jane E Blanton 14
William Blanton 7
James Blanton 1

William J. Blanton married twice. Circa 1864, he married Temperance Jones, the daughter of Nathaniel and Anna Humphries Jones. They were enumerated on the 1880 Limestone Springs, South Carolina, Census:

William Blanton 37
Temperance Blanton 38
Andrew J. Blanton 14
Annie L. Blanton 11
Mary M. Blanton 9
John I. Blanton 6
Joseph D. Blanton 2

Mr. Blanton's second wife was Julia Ellen Gordon. She brought three children to the marriage: Elizabeth, Benjamin, and John Gordon. William and Julia Blanton added four additional children to the family: Landrum Brown Blanton, Amy Margaret Blanton, Eva Blanton, and William Thomas "Willie" Blanton.

The family dynamic was explained further in the obituary of John I. Blanton, son of William and Temperance Blanton. Among the surviving family members was: his step-mother, Mrs. Julia Blanton.