That was the only possible sentence for Michael Chadd Boysen, 27, after he entered a guilty plea to aggravated murder charges Oct. 4 for the killings last March of Robert Taylor, 82, and Norma Taylor, 80, at the Renton home where they had thrown him a party.
King County prosecutors did not seek the death penalty.
Defense lawyers had asked for a 40-year sentence because of Boysen's history of mental illness and suicide attempts.
Boysen was found with self-inflicted cuts when he was arrested after a standoff at a Lincoln City, Ore., motel three days after the killings.
King County Superior Court Judge Douglas North said he saw no basis to deviate from the law, even if that were possible.
Boysen's mother tearfully addressed the court prior to her son's sentence, recalling the last time she saw her parents alive after the end of the party welcoming Boysen home from prison.
"I looked back in my rearview mirror, there on the front porch was my mom, my dad, and my son waving goodbye, my mom signing 'I love you,' " Melanie Taylor said. "It brought tears to my eyes to see the three of them standing on the porch and to have my son back with my family."
She remembered her parents as "true examples of unconditional love."
"I miss my parents more than you will know, but I take pride in seeing their character, their values and love shine in my family," Melanie Taylor said. "Whatever transpired that horrible night, I know my parents would have done anything to help their grandson, even if it meant giving up their lives to do so."
She then offered forgiveness to her son.
"I will never understand what happened on March 9th but I want you to know I will not... and do not judge you and above all, I do forgive you."
But it was when Boysen's aunt was giving her statement to the court admonishing the choices her nephew had made that Boysen became angry, stood up and screamed profanity. He was quickly admonished by the judge and told to sit back down.
Boysen then read a statement in which he complained about police, prosecutors and jail guards.
He admitted he was a difficult prisoner, with 14 instances of self-harm and suicide attempts over seven months in jail.
He had an urge to die and compulsion to harm himself "that I can get out of my head," but it wasn't helpful to keep him strapped to a board, Boysen said.
Boysen said he loved his grandparents who were like second parents after his parents divorced when he was a teen.
"I have remorse. I am sorry whether my family chooses to believe it or not," he said. But at another point he said, "An 'I'm sorry' at this point doesn't really seem to cut it."
Boysen had completed a burglary sentence when the Taylors picked him up at the Monroe Correctional Complex and held a welcome home party for him that Friday night.
The couple's bodies were found that weekend by their daughter - Boysen's mother.
They were in the closet of their guest bedroom partially dressed in their pajamas. Both had "severely dark-bruised ligature marks around their necks," charging papers said.
A bloody shoelace remained partially wrapped around Norma Taylor's neck.
Detectives found emptied envelopes that held $5,200. Credit cards belonging to the couple, her cellphone and their car were also gone.
Boysen went on a shopping spree, spending around $1,400 at Fred Meyer and Walmart to buy an iPad, a laptop, CDs, and a pre-paid cellphone, detectives said.
He was caught after the motel manager recognized him from television news reports. He had signed in using his real name.
Boysen was previously in prison from 2006 to 2011 for four robbery convictions, related to an addiction to narcotic painkillers, the state Department of Corrections said.