Justin Ross Harris, 33, originally of Tuscaloosa, Alabama, is also charged with cruelty to children in his son's death, Cobb County police spokesman Dana Pierce said in a statement.
Harris, who lives in Marietta, told investigators that he was supposed to drive his son to daycare, but instead drove straight to work and didn't realize the boy was strapped into his car seat until the ride home Wednesday afternoon, police have said.
Temperatures in the metro Atlanta area that day reached the low 90s. Harris pulled his family's SUV into a nearby shopping center and began trying to revive the child, police have said.
"It's just a terrible, God-awful situation," Cobb County District Attorney Vic Reynolds told WSB Radio in Atlanta. "The thought of what a 22-month old child went through during those seven or so hours ... you don't even want to imagine it." The murder charge doesn't suggest that Harris intended to kill his son, but does indicate that child neglect factored into the boy's death, Reynolds said.
Harris is being held in the Cobb County jail. It was not immediately clear if he has an attorney. The Cobb County Medical Examiner's office will perform the boy's autopsy, Pierce said.
In another case Thursday, a 20-year-old Augusta, Georgia, woman was charged with child neglect after a Richmond County sheriff's deputy climbed through a sunroof to pull her infant son from the backseat of her unattended vehicle. The woman had draped a white sheet over the boy's car seat and left him alone while she took a final exam for cosmetology school, sheriff's officials said. The boy was treated and released to his grandmother.
Officials from the Georgia Department of Early Care and Learning said the incidents are timely reminders of the agency's "Look Again" campaign.
The public awareness initiative, launched last month, reminds parents and childcare workers always to double check a vehicle for children before locking the doors and walking away.