Authorities arrested the baby's father, 49-year-old Joseph Daniels, during a traffic stop Saturday morning.
The baby's mother, 32-year-old Angelina Williams, was arrested earlier this week.
Police say the two tried to steal copper wiring in Upper Chichester on Monday.
Mother and father allegedly leave baby behind after alleged criminal behavior
They took off in a Jeep, leaving behind a second vehicle at the scene.
That car was towed to the police station, where an officer found the baby inside.
The four-month-old boy was not injured.