The correct answer to this open question is the following.
The South Carolinian that spoke out against integrating public schools in South Carolina was Strom Thurmond.
Strom Thurmond (1902-2003) was a politician and Congressman from South Carolina. For almost 48 years he was a Senator from his state. He was a racist and opposed the Civil Rights Act of 1964 and did not hide his opposition to integration. To the opposite, he always supported racial segregation in South Carolina.