Benitez had been a fugitive with his son for four years until he showed up Tuesday during the standoff at Tai Pan restaurant in El Monte just after 3:20 p.m.
Authorities first used a flash-bang grenade before gunfire was exchanged between cops and Benitez.
"Sometime during this negotiation, the door flew open. There was an exchange of gunfire between the SWAT officers and the suspect, and the suspect went down," said Lt. Liam Gallagher from the L.A. County Sheriff's Department.
Benitez was declared dead at the scene.
Police said Benitez had used his son as a human shield, complicating authorities' efforts to keep the boy safe. Negotiations had failed completely, and Benitez threatened to kill his son, placing a gun to his child's head several times, according to police.
The child was hit in the thigh during the exchange of gunfire, and is currently listed in critical but stable condition. He is expected to make full recovery.
Witnesses said Benitez had looked like a transient who picked up a little boy. They were unaware of the relationship between the two and called police because he looked suspicious.
According to the FBI, Benitez is a former child actor who starred in commercials, TV shows and motion pictures, including Pee Wee's Playhouse and Stand and Deliver.