Justin Ross Harris, 33 left his 22 month old son Cooper in the car for over eight hours in searing 55c heat whilst he did a full days work.
He has been charged with murder and cruelty to children in the second degree.
Police have since received anger and backlash for their decision.
A peitition signed by over 11,000 people on website Change.Org calls for the authorities to drop the charges against the father.
One comment read: 'This could happen to anyone. Anyone. Charging a grieving father is abusive.'
District Attorney Vic Reynolds told WSB Radio: 'When a suspect is charged with a felony - cruelty to children in the first degree - which results in the loss of life, a murder charge is appropriate'.
However police claim that Harris returned to his car where the toddler was in the backseat during the day to place an object in the vehicle.
They also said the father had been searching online for how long it would take for an animal to die in a hot car.
Cobb County Police Sergeant Dana Pierce told CNN that the circumstances of the case had changed since they were first reported.
The father stated that he didn't realise anything was wrong with the child until he started driving home at the end of the day.
He stopped the car when he realised that his son was completely unresponsive.
Witness Dale Hamilton saw Harris attempt to give his son CPR, and has told that the father was constantly saying 'What have I done? What have I done?'.
Police had to restrain him when they arrived as he was so distressed.
Sadly, stories of children being left alone in hot cars are far more common than they should be.