Lewis Conway Jr. is campaigning in the same district where he killed the man in 1992.
Conway said it was self-defense and struck a plea deal for voluntary manslaughter.
He spent eight years in prison and 12 years on probation.
Conway had his voting rights restored five years ago.
However, state rules on convicted felons running for office are vague. The Secretary of State's office also said it's never happened before.
Conway says he is exploring legal options to clear a path to run.