His resignation comes after The College Republican National Committee (CRNC) condemned white supremacy and called on leaders in CRNC who supported "Unite the Right" to resign.
"Advocates for white nationalism, racial supremacy of any kind, and terrorism have no home in the Republican Party or anywhere else in America," Chandler Thornton, the CRNC national chairman, told King 5. "The National Executive Board for the College Republican National Committee calls on leaders in our organization who may support or condone these events to resign immediately."
Allsup claims he has been planning to resign before he went to the rally, according to King 5.
The "Unite the Right" rally rocked the Charlottesville community after protests became violent. Apparent white supremacist James Fields rammed his car into a crowd of demonstrators, killing 32-year-old Heather Heyer.
The rally was called in response to a plan to remove a statue of Confederate general Robert E. Lee from a park in Charlottesville.