Georgia man Justin Ross Harris, 35, was found guilty last month of felony murder, as well as counts of first and second-degree cruelty to a child in connection to the June 2014 death of the 22-month-old boy, Cooper.
The former Home Depot web developer was also convicted of criminal attempt to commit sexual exploitation of a child because of explicit texts he sent to a teenage girl.
Looking exhausted and wearing an orange prison jumpsuit in the courtroom, Harris said only "yes" and "no" in response to Cobb County Superior Court Judge Mary Staley Clark.
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His attorneys declined to offer any evidence on Monday to mitigate his sentence.
During the trial, they had described Harris as a "flawed but God-fearing man" who loved his only child.
They said he simply forgot to take the boy to his daycare center after a father-and-son breakfast.
The defense lawyers left court without comment after the sentencing.
They have said they will appeal Harris's conviction, but have not yet said on what grounds.
Prosecutors had argued he left the child to die so he could enjoy a child-free lifestyle and pursue other women, including teenagers and prostitutes.
Phone and internet records showed he was texting with other women even as his son was left for seven hours outside his workplace.
Vic Reynolds, the Cobb County district attorney, told reporters that his office gets no joy from winning the case, but that they have found "justice for Cooper Harris".
Police testified that Harris showed little emotion over the boy's death, except in what seemed to be staged outbursts.
It was also revealed at the trial that he visited his car during a lunch break, but said he did not see his son in the back seat.
