Justin Ross Harris, 33, of Marietta, was found guilty on all 8 counts in the death of his 22-month-old son Cooper Mills Harris.
Harris argued that he forgot his son was in the back seat of his SUV when he arrived at work at a Home Depot in Cobb County on June 18, 2014.
A Glynn County jury on Monday deliberated for several days before finding Ross guilty of malice murder, 2 counts of felony murder, sexual exploitation of children, disseminating of harmful material to minors, and other charges.
As a normal routine, Ross took his son to a Chick-fil-A restaurant for breakfast. His plan was to drop the boy off at his daycare after leaving Chick-fil-A.
But on that fateful day, Ross left the restaurant and missed the turn to Cooper's daycare less than a minute later.
The jury did not believe the defense argument that Ross forgot his son was in the SUV. The prosecutors pointed out that Cooper was stuffed into a child's safety seat that was too small for his size. Additionally, the car seat was facing backward rather than forward.
The jury watched surveillance video footage from Home Depot that showed Ross went to lunch with 2 co-workers and purchased light bulbs after lunch.
The video shows a co-worker dropping Ross off at his SUV. Ross opened the driver's side door and tossed the bag of light bulbs onto the passenger seat.
Investigators say the car seat could clearly be seen through the windshield from outside the driver side door.
Ross claimed he discovered his son dead when he left work that evening and spotted the child in the rear view mirror while making a turn.
An investigator told the jury he detected a "sickly sweet" odor of death in the SUV that day.
Prosecutors said Harris sent photos of his genitals to a 15-year-old girl with whom he sexted while his son was dying in the hot car.