Superior Court Judge William Mudd rejected an angry plea by defense attorney Steven Feldman to spare the life of Westerfield, 50, a design engineer with no history of violence, because of inflammatory media coverage and improper conduct by police.
"America has changed — it's where capital-murder trials have become summer entertainment," Feldman said. "Don't acquiesce to the mob mentality of this community."
Mudd criticized the media but said the trial was not adversely affected by coverage or the alleged attempt by San Diego detectives to talk to Westerfield without his attorneys present after his arrest.
Brenda van Dam, Danielle's mother, tearfully told Mudd that "our precious Danielle was taken by a monster thinking only about his own self-gratification, not the sweet, little child he was harming and about how his crime would affect her family, the community and the world."
Looking at Westerfield, her former neighbor, she said, "It disgusts me that your sick fantasies and pitiful needs made you think that you needed Danielle more than her family."
Prosecutors, who called Westerfield a "cold-hearted child killer," said he harbored sexual fantasies about small girls. During the trial, evidence showed that Westerfield kept child pornography on his home computer.
Westerfield, slumped in his chair, declined an offer by Mudd to speak before sentencing. He also declined to speak to officials of the Probation Department for a background report that judges use to help determine sentences. His only prior conviction was for drunken driving.
The jury that convicted Westerfield on Aug. 21 sentenced him to death. Under California law, the trial judge decides whether to accept the jury's sentence or reduce it to life in prison without the possibility of parole.
Westerfield was convicted of taking Danielle from her bedroom on the night of Feb. 2 and then leaving her nude body in a rural area 45 miles from the neighborhood where Westerfield and the van Dams lived three doors apart.
Twice divorced, with grown children, Westerfield lived alone. As an engineer, he assisted in the development of medical-rehabilitation devices and undersea-exploration equipment and was known by co-workers as a "regular guy" who was generous, bright and amiable.
Still, a former live-in girlfriend testified that he could become "physical" when intoxicated.
In court, Feldman argued that Westerfield was not the "worst of the worst" and did not deserve the death penalty. But Mudd noted Westerfield's apparent lack of remorse for the crime.
Danielle was at home with her father and two brothers when Westerfield allegedly entered the house and kidnapped her from her bed.
Because her body was severely decomposed by the time she was found, the county medical examiner was unable to determine how or when she was killed or if she had been sexually molested.
Westerfield was linked to the murder by fibers, blood and fingerprints found in his home, in his recreational vehicle, and on the corpse. The "smoking gun" was said to be the discovery of Danielle's blood on Westerfield's jacket and her hair in his bedroom.
Westerfield becomes the 617th inmate on California's death row. The van Dams on Thursday filed a wrongful-death suit against Westerfield to prevent him from profiting from selling his story.