The boy was being pushed down Lumley Street in Granville by his father at around 5.30pm on Tuesday when a Toyota Tarago careened off the road and hit the stroller.
The boy and his pram became trapped between the vehicle and the brick fence of an apartment building.
Paramedics battled to save the boy on the scene for more than an hour, reviving him after he suffered a cardiac arrest. He was transported to Westmead Children’s Hospital but later died there.
The boy’s father who was pushing the stroller at the time of impact is uninjured. The 37-year-old driver of the car has head and abdominal injuries.
Eyewitnesses told police the Tarago had hit another car before it left the road. The driver and passenger of the other car were also assessed by paramedics and didn’t require treatment.
Any witnesses, who have not yet spoken to police, are urged to contact Crime Stoppers on 1800 333 000.