According to WSB-TV, the child was checked out by Emergency Medical Services and released to his grandmother.
Police said the Kia Sorrento was stolen at a Shell station on Roosevelt Highway around 5:30 p.m.
WSB-TV's Michael Seiden learned from police that the child's father left him in the car alone while he ran inside the gas station with the SUV running. The slider thief jumped behind the wheel and took off, police said.
The SUV was found a short time later at the Atlanta airport with the child still inside. The suspect has not been caught.
Seiden learned that the father, identified as Larry James, 22, has since been charged with second-degree cruelty to children.
Police said the father not only left his son in the car, but left the car running.
Surveillance video from the gas station shows the moment the father realized his car was being stolen with his child inside:
Seiden talked to Prem Kunwar, the manager of the gas station, who gave him the footage of the moment the SUV was stolen and the father realized his baby was inside.
"Right after he took the car, the dad came back to me and said, 'Oh! I got the baby in the car! Call 911!'" Kunwar said.
"It's a danger for everybody," Kunwar added. "Every mother and dad should know about this."
Prem said minutes before the theft happened, he got worried when he saw a familiar face roaming the parking lot.
Union City police said the suspect is a man with dreadlocks and a black T-shirt with black pants.
"He comes in here all the time and steals the candy," Kunwar said.
Before he could confront the man, the suspect was gone.
"I did follow him, but it was too late," Kunwar said. "Too late."
Police said they believe he's responsible for additional slider crimes.
Investigators said the baby is doing well.
Kunwar is just happy the baby is safe.
"I don't care about the car," Kunwar said. "We can buy the car, but we cannot buy the baby."