Laura Mallory, who argued the popular fiction series is an attempt to indoctrinate children in witchcraft, said she still wants the best-selling books removed and may take her case to federal court.
"I maybe need a whole new case from the ground up," said Mallory, who was not represented by an attorney at the hearing.
Superior Court Judge Ronnie Batchelor's ruling upheld a decision by the Georgia Board of Education, which had supported local school officials.
County school board members have said the books are good tools to encourage children to read and to spark creativity and imagination.
J.K. Rowling's Harry Potter books, published by London-based Bloomsbury Publishing PLC, tell stories of children with magic powers. They have been challenged numerous times since 2000, making them the most challenged texts of the 21st century, according to the American Library Association.
At Tuesday's hearing, Mallory argued in part that witchcraft is a religion practiced by some people and, therefore, the books should be banned because reading them in school violates the constitutional separation of church and state.
"I have a dream that God will be welcomed back in our schools again," Mallory said. "I think we need him."