Christopher Canon was 15 when he shot 18-year-old Michael Price Jr., of Oakland, at the Metreon at Fourth and Mission streets on Nov. 11, 2007. He was arrested nearby after the shooting, and was charged as an adult.
Canon, a San Francisco resident who is now 19, was upset that Price wasn't moving quickly enough down an escalator outside a video arcade at the complex, prosecutors said.
Canon's attorney, David Simerly, said Price was the attacker, and that Canon shot him in self-defense.
A mistrial was declared in the case last November when a San Francisco Superior Court jury deadlocked on whether Canon should be convicted of first- or second-degree murder.
Prosecutors retried the case with a new jury, and after two days of deliberations, the jury declined to convict Canon of first-degree murder, but found him guilty of second-degree murder with an enhancement for the use of a firearm.
The foreman of the jury, who did not want to be named, said outside of court, "We did feel for sure that they had the right person," but "we had a problem with whether or not it fully met the standard of first-degree murder."
Canon faces a sentence of 40 years to life in state prison for the charges.
Simerly called the result of the case "appalling."
He said security footage from the building shows that Price was the aggressor and that Canon was backing up when he fired four shots at him. Simerly also criticized the stiff sentence for someone who was so young at the time of the shooting.
"It's nauseating that we have a country that subjects a 15-year-old to that," he said. "They do not perceive situations the way adults do."
Canon will return to court to be sentenced on July 8.