Justin Smith, 26, was arrested in Atlanta back in March after four years on the run.
The victim, 21-year-old Dianna Brice, was last seen in Delaware County getting into a car with Smith.
Her body was later found in Southwest Philadelphia, with multiple gunshot wounds to the head.
"I will never, ever forgive this man for what he did to my daughter, my unborn grandson, and her son that is now nine years old," Brice's mother, Betty Cellini, said.
Smith was convicted of first- and third-degree murder.
He has been sentenced to life in prison without parole.