The judge denied a motion to reduce Magallon's punishment to life in prison Thursday, allowing the jury's death penalty verdict to stand.
Magallon was convicted of first-degree murder and attempted robbery in the 2004 killing of Captain Michael Sparkes.
Sparkes, who was confronted while riding his bicycle near Compton, was shot nine times with an assault rifle.
Sparkes, a 53-year-old law enforcement veteran, died at Harbor-UCLA Medical Center, where he had supervised the hospital's security force.
Superior Court Judge Kathleen Kennedy says Magallon failed to show remorse during the penalty phase of the trial.
"Quite frankly, I don't think he feels any remorse," Kennedy said.
"Is the defendant a predator? I think he is a predator," she added.
Magallon's attorney contends that a co-defendant who's serving 50 years to life was the driving factor behind the murder.
Outside court, the victim's widow told reporters, "I'm just glad it's over with. It's been five years."
City News Service contributed to this report