It happened around 2:30 a.m. Thursday in the eastbound lanes of the Southern State Parkway near exit 42.
Police say the wrong-way driver was fleeing an attempted traffic stop by a Suffolk County deputy sheriff.
The deputy spotted the wrong-way vehicle, traveling westbound in the eastbound lanes, and attempted to pull over the vehicle, but the driver failed to stop.
Concerned about the safety of driving into oncoming traffic, the deputy broke off attempts to pull over the vehicle, and switched to the westbound lanes to follow the driver while in the correct flow of traffic.
When he was able to switch back into the eastbound lanes, he came upon a four-car crash at exit 42.
The deputy found the 9-year-old victim in the back of the vehicle. First responders performed CPR and used an automated external defibrillator to try and save the child's life.
The child's mother, a Centerport resident, was taken to Good Samaritan Hospital in West Islip with non-life-threatening injuries.
Investigators believe she had been driving the wrong way for some time, perhaps even on the Sunrise Highway, before the crash.
She was administered field sobriety tests following the crash. Charges are expected.
The occupants of the other three vehicles involved in the crash were taken to South Side Hospital and Good Samaritan Hospital. All of their injuries appear to be non-life-threatening.
The force of the crash separated the engine from the wrong-way vehicle and threw it into oncoming traffic..
The Suffolk County District Attorney and the state Attorney General's Office responded and will be investigating the crash.