A 14-year-old boy and his father have faced court for the first time charged over the murder of four people in a gun attack at a Georgia high school.

Colt Gray, a pupil at the school, was arrested shortly after the shooting on Wednesday at Apalachee High School in Winder, near Atlanta. He appeared in person in court on Friday, charged with four counts of first degree murder.

His father, 54-year-old Colin Gray, is charged with involuntary manslaughter, second-degree murder and child cruelty, and is accused of "allowing" his son to possess an AR-15 rifle.

The judge clarified that the 14-year-old would not face execution, after first stating the maximum penalty was death.

Those killed were identified as Mason Schermerhorn and Christian Angulo, both 14, and teachers Richard Aspinwall, 39, and Cristina Irimie, 53.

The court appearances were the first for both Grays. CNN reported that families of victims were seated in the first row of the court. One woman held a stuffed animal of a Disney character in her arms.

Wearing a green t-shirt, the 14-year-old suspect spoke little other than to acknowledge that he understood the charges he faces.

The judge acknowledged heightened public interest in the case. Because of this, news cameras were allowed to record and livestream the hearings.

He initially told Colt Gray that the maximum penalty for his charges was death or life in prison, but later called the accused back to clarify that under-18s can not be put to death.

Colin Gray, the father, appeared distressed at some points during his hearing. Wearing a striped shirt, he was seen rocking back and forth after the judge finished speaking.

The judge told him he faced a total of 180 years in prison for his charges.

Both of the accused were told that they had the right to a "speedy and public trial by judge or jury". Neither requested a bond and no pleas were entered.