He initially pleaded not guilty by reason of insanity but that plea was withdrawn.
The defence then urged Judge Jean Leonard, sitting without a jury in Riverside, 60 miles from Los Angeles, to convict Hall of a lesser offence of voluntary manslaughter.
A psychologist told the court the boy had been conditioned to violence by years of physical, emotional and probable sexual abuse.
The boy himself said in a videotaped interview with police that he did not think he would get in trouble for shooting his father.
He described seeing an episode of the TV drama "Criminal Minds" in which a child killed an abusive father and was not arrested.
Prosecutor Michael Soccio told the court Jeffrey Hall was a loving father despite his neo-Nazi ties.
He said Joseph Hall, who lived with four siblings, shot his father because he thought he was planning to divorce his stepmother, to whom he was close.
The boy's younger sister said he had plotted the shooting days in advance.
Prosecutors also said the boy had a history of violence that dated back to kindergarten when he stabbed a teacher with a pencil.