Sinei Aunei pleaded guilty to manslaughter and negligent driving causing injuries.
He was the driver of a delivery truck which collided with a minivan in June this year on Savai'i island, killing a woman and her four-year-old son.
The woman's 17-year-old son, who was the driver at the time, received serious injuries.
According to the police summary of facts, Aunei had been drinking home-brew with a friend, and was drunk before he drove the truck.
Aunei's employer paid for the funeral of the two victims, and bought a new car for the family.