But a legislator says the 1985 law, known as the "Make My Day" law, may have been misinterpreted by the jury.
Gary Lee Hill, 24, faced charges in the 2004 killing of 19-year-old John David Knott, who along with three others had assaulted Hill in his home.
Hill was accused of firing a shot into a car that Knott was driving. Knott crashed into a house and died from a single gunshot wound to the back, authorities said.
"It's a miscarriage of justice," Sen. Jim Brandon, who helped craft the law, said. The law meant a home's door to be a threshold for an illegal entry, not down the street, he said.
Prosecutor Lisa Kirkman said the law says deadly force can be used "if the shooter reasonably believes the other person might use physical force against the home dweller."
According to testimony, Knott and the others showed up at Hill's house after an argument over a missing purse.
"Gary went through this horrible and traumatic event," said defense attorney Ted McClintock. "They promised they were going to come back in. They had already come back once."