Eddie Ray Routh stood impassively as the judge read the verdict finding him guilty of killing Chris Kyle and his friend Chad Littlefield, and then polled the jurors.
It was a unanimous decision, and one that reached in less than two and a half hours, ending a trial that played alongside recently released American Sniper, a film about Kyle.
Routh was sentenced to life in jail without parole.
"We've waited two years for God to get justice for us on behalf of our son," said Judy Littlefield, Littlefield's mother. "And as always, God has proven to be faithful."
Routh, a former US Marine, had shot Kyle and Littlefield multiple times in the back at a Texas shooting range in 2013 where they had taken him as part of an effort to help him deal with post-war trauma.
That he killed the two men was never in dispute. His defense team tried to argue that he was not guilty by reason of insanity, and should be sent to a mental institution.
His attorneys used a text message from Kyle to Littlefield from that fateful day as proof. Kyle had said, "This dude is straight-up nuts." Littlefield asked him to watch his back.
In interviews to police and reporters, Routh said he killed them because he feared they would kill him instead and that they wanted his soul, and he spoke of half-pigs and half-humans.
The prosecution, backed by experts, argued Routh knew exactly what he had done, and has started building towards an insanity plea from the time he was arrested.
After killing the two men, Routh stopped at a Taco Bell, a Mexican fast-food chain, and then visited relatives. After his arrest, he told police officers he was paranoid and schizophrenic.
Texas state is extremely tough on insanity pleas, and Routh's attorneys had a nearly insurmountable task of making that stick. The release of the movie recently made it worse.
They tried to delay the trial arguing the hype around the movie would influence the jurors, most of whom had probably watched it. But that didn't work either.
"We all had our strong feelings… ultimately a unanimous decision, multiple times," one of the jurors told ABC's George Stephanopoulos Wednesday morning.