Multiple shots were fired in the courtyard of Price Middle School just south of downtown around 1:50 p.m. and the one boy was hit, Atlanta Police Chief George Turner said. In the aftermath, a teacher received minor cuts, he said.
The wounded boy was taken "alert, conscious and breathing" to Grady Memorial Hospital, said police spokesman Carlos Campos. He was expected to be released Thursday night.
Police swarmed the school of about 400 students after reports of the shooting while a crowd of anxious parents gathered in the streets, awaiting word on their children. Students were kept at the locked-down school for more than two hours before being dismissed.
Investigators believe the shooting was not random and that something occurred between the two students that may have led to it.
Schools Superintendent Erroll Davis said the school does have metal detectors.
"The obvious question is how did this get past a metal detector?" Davis asked about the gun. "That's something we do not know yet."
The armed resource officer who took the gun away was off-duty and at the school, but police didn't release details on him or whether he is regularly at Price. Since 20 children and six adults were shot to death at Sandy Hook Elementary School in Connecticut in December, calls for armed officers in every school have resonated across the country.
Hours after the Atlanta shooting, several school buses loaded with children pulled away from the school and stopped in front of a church about a half-block away. Parents tried boarding the buses. Police who initially tried to stop the parents, relented and screamed, "Let them off!" about the students.
James Bolton was at work when his sister called saying a teen had been shot at his son's school and was in the crowd as parents began swarming the fleet of buses.
"Move, I see my son, I see mine!" he said, running up to embrace James Bolton Jr. "As long as I got this one back I'm OK," he said, holding his son's head against his chest as parents nearby frantically searched for their children.
Bolton Jr. said he was in class when the intercom sounded and a school official announced the building was under immediate lockdown.
"They told us we had to be quiet," Bolton told The Associated Press. "They said something went on in the courtyard." Bolton said he was unaware that anyone had been shot until a reporter asked him about it.
Shakita Walker, whose daughter is an eighth-grader at the school, said she received a text from her that said, "Ma somebody's shooting and somebody got shot." Walker, who works at another school, said she jumped in her car and was thinking "just hurry up and get there."
Walker said her daughter called to tell her that they were being kept in the gymnasium, but she said she was anxious to see her to make sure she was OK.
The fear and anxiety was palpable in the crowd, as one person yelled, "Does anyone know what happened?"
Superintendent Davis sympathized with concerned parents who complained that it took too long for students to be released from the building. He said emergency procedures were followed according to protocol and school district officials would meet Friday to review their response. Calls to the school district were not immediately returned.
Mayor Kasim Reed condemned gun violence in a statement shortly after the shooting and said counselors were at the school to meet with students, faculty and family members.
"Gun violence in and around our schools is simply unconscionable and must end," Reed said. "Too many young people are being harmed, and too many families are suffering from unimaginable and unnecessary grief."
Outside the school, Laquanda Pittman said she still hasn't heard from her sixth-grade son. She said she heard the news of the shooting on TV and immediately came to the school.
"All types of stuff went through my head. I'm wondering whether it was my child who got shot, is my child OK, did he see what happened?" Pittman said.
She said she just wants to see her son.
"As a parent, you just think you can send your child to school and you hope they come home OK," she said.