Judge O’Neall was born in Newberry County, the son of honorable, debt-paying Quaker parents. Educated in local schools and South Carolina College (second honor graduate, 1812), he studed law under John Caldwell and Anderson Crenshaw and was admitted to the practice of law and equity in May, 1814.
In 1818, he married Helen Pope, daughter of Captain Sampson Pope and his wife, Sarah Strother Pope of Edgefield.
Judge O’Neall’s remarkable personality made him a leader among men in various fields of endeavor — Chief Justice of South Carolina, a judge for 35 years, a trustee of South Carolina College for 40 years, first President of the G&C Railroad Company, Speaker of the House of Representatives and Major General in the Militia. He excelled as a lecturer and as author of many articles and books, including The Annals of Newberry and The Bench and Bar of South Carolina. A staunch Unionist, he succeeded against keen competition, despite the unpopularity of his political views.
During a long and useful life, he contributed mightily to knowledge, jurisprudence, education, temperance, religion and agriculture.