Orange County Superior Court Judge Frank F. Fasel imposed the sentence recommended by the jury that convicted 29-year old Skylar Deleon of killing Tom and Jackie Hawks of Prescott, Ariz.
"It is the judgment and order of this court you shall suffer the death penalty as to each count," Fasel said.
Deleon, of Long Beach, feigned interest in buying the couple's nearly half-million-dollar yacht and killed them during a test cruise out of Newport Harbor in 2004. The Hawkses' bodies were never found.
Deleon was also convicted in the 2003 killing of Jon Jarvi, an Anaheim man he met on a work furlough program.
"It is difficult to imagine a case where it's more cold-blooded and calculated than this series of murders," prosecutor Matt Murphy said after the sentencing. "I can't imagine a situation that is more deserving of the ultimate punishment."
Deleon looked straight at the judge while the sentence was read and appeared to show little emotion. He exchanged whispers with his attorneys before he was led out of the courtroom, his hands cuffed to a chain circling his waist.
Defense attorney Gary Pohlson declined to comment afterward.
Fasel said he decided to impose the death penalty in part because of the horrific nature of the murders and the anguish that the three victims surely suffered before their deaths.
Deleon and his then-wife Jennifer Henderson crafted the plan to kill the Hawkses to steal their boat and savings.
After the yacht killings, prosecutors said, Deleon and Henderson scrubbed the boat clean with bleach wipes in Newport Harbor.
Henderson was convicted in 2006 of murder and murder for financial gain and was sentenced to two terms of life in prison without parole.
Another defendant, John Fitzgerald Kennedy, was also convicted in the murders earlier this year. The jury has recommended the death penalty for Kennedy, who is set to be sentenced in May.
Myron Gardner, who was initially also charged with the murders, pleaded guilty last month to accessory after the fact and murder charges against him were dismissed. Alonso Machain, who testified that he and Kennedy were on the boat with Deleon the day of the killings, also faces murder charges.
Several of the victims' relatives pleaded with Fasel on Friday to impose the death penalty on Deleon.
Jeff Jarvi told the judge he constantly wakes up gasping for breath, imagining he is tied to an anchor or crawling on the desert floor - much as his brother did before he died.
"It doesn't go away," Jarvi said. "It continues like a roller coaster that never ends."
Ryan Hawks, Tom's son, said he hoped that Deleon's two children would never know what their father did, or how he used his young daughter to help win the trust of the Arizona couple before heading out to sea.
"No one wants to know they were used as decoys or fakes to murder my parents," Hawks said after the sentencing.
Deleon will be transferred to the state prison in San Quentin. His case will automatically go to an appeal.
Last year, jurors deliberated nearly two days in the penalty phase of Deleon's trial before recommending death.
Pohlson had pleaded with jurors to spare his client's life, arguing that Deleon was abused by a drug-dealing father, which left him predisposed to violence.
Murphy had urged jurors to recommend death for Deleon for the cruel, callous way he killed the Hawkses and Jarvi, whose throat was slashed and body dumped in Mexico. Deleon killed Jarvi after receiving money from him for a supposed business deal that he used to pay his own bills.
Deleon was once a child actor under the name John Liberty.