The deputy, a 17-year veteran of the South L.A. station, was hospitalized at Harbor-UCLA Medical Center in Torrance with minor injuries.
"We believed initially he had broken legs, but he did not sustain broken legs," said L.A. County Sheriff Lee Baca. "He has severe bruising on his back."
The Sheriff's Department said the shooting took place on the 11400 block of South Vermont Avenue near Imperial Highway in a strip mall parking lot.
Baca said deputies responded to a 911 call at 2:30 p.m. Friday.
A woman had been in a car with her boyfriend and her two kids, 8 years old and 7 months old, when the man kicked her out of the car.
Detectives say the suspect drove down the street and left the children in a Ralphs grocery store parking lot. Ralphs employee Irma Martinez and her co-workers helped the girl, who was in tears and holding her baby sister.
"She was very nervous, and she was crying really bad, so we were trying to help her," Martinez said.
While deputies were questioning the woman, who was in fear for the safety of her children, the suspect returned in the car to the scene and accelerated, hitting several other vehicles. The multiple-collision force caused the investigating deputy to be struck and thrown about 15 feet in the air.
A second deputy, due to the lethality of the force of the suspect's driving, reached into the suspect's car and fired three shots inside the car, killing the suspect.
The deceased suspect was believed to be a gang member. He has not been identified.
The woman and her two children were not injured, and they have been reunited.