Nikolas Cruz, 23, additionally confessed to 17 counts of endeavored murder for those he harmed in the assault on Marjory Stoneman Douglas High School.
He faces the chance of capital punishment or life in jail.
One of the deadliest acts of mass violence in US history, the occurrence turned into a revitalizing sob for firearm control activists.
Mr Cruz was 19-years of age when he shot dead 14 understudies and three workers with an AR-15 rifle at his previous school. Another 17 individuals were injured.
The case will currently make a beeline for a punishment preliminary where attendants should decide if Mr Cruz is saved capital punishment to confront existence without the chance for further appeal.
Judge Elizabeth Scherer has said she trusts that the case – for which huge number of legal hearers should be screened – can start in January.
In court on Wednesday, Judge Scherer asked Mr Cruz how he argued to each murder.
Following the request, Mr Cruz sorrowfully tended to the adjudicator and the casualties’ families.
“I’m exceptionally upset for what I did and need to live with it consistently,” he said. “If I somehow happened to get another opportunity, I would do my best to help other people.”
Mr Cruz added that he has “bad dreams” about his wrongdoing and “can’t live with” himself. He additionally said that he accepts that the US would “improve if everybody would quit partaking in pot”.
Attorneys addressing Mr Cruz had over and again said that he would concede if capital punishment was not thought of. Last week, his lawyer, David Wheeler, let the appointed authority know that Mr Cruz’s legal counselors were requesting that the court force 17 continuous life sentences for the slaughter.
The proposition had been dismissed by investigators, who in prior court reports said they would look for his execution and demonstrate that the wrongdoing “was particularly egregious, monstrous or brutal”.
Following the meeting, Tony Montalto – whose 14-year-old little girl Gina was killed in the shooting – let the Associated Press know that Mr Cruz’s blameworthy requests “are the initial phase in the legal interaction”.
“Be that as it may, there is no change for my family,” he added. “Our splendid, delightful and darling girl Gina is gone while her executioner actually partakes in the gift of life in jail.”
Walk for Our Lives, a weapon law change association began by Parkland survivors in the wake of the shooting, said in an explanation that it has “no remark” on Mr Cruz and “a liable supplication won’t eradicate the past, and it won’t bring us harmony”.
“What is clear is that weapon viciousness is a fundamental emergency and an extraordinarily American plague,” the assertion said.
The association added that it is “shocked and nauseated that policymakers proceed to waffle and mess around” as opposed to carry out changes. “We are not settled, we are as not really set in stone as anyone might think possible.”
Last week, Mr Cruz confessed to a different charge of endeavored disturbed battery and three other crime accusations coming from an assault on a prison monitor nine months after the shooting.
On Wednesday, Judge Scherer condemned Mr Cruz to 26 years in jail for the prison attack.
In a meeting on Friday, he recognized that his conviction in the prison attack could turn into an “irritating variable” in deciding if he will be executed.
In front of Mr Cruz’s blameworthy request, Fred Guttenberg, whose little girl Jaime was killed in the shooting, let CBS News know that he trusted that Mr Cruz would pay for his wrongdoings “with his life”.
“My little girl ought to be experiencing the greatest long periods of her life. My child heard his sister have chance and his life is perpetually affected. My better half and I had two youngsters that executioner took this from us.”
Mr Cruz had been ousted from the school in 2017. Understudies and staff later portrayed him as an “pariah” and miscreant.
He had recently been explored by neighborhood police and the Department of Children and Family Services subsequent to posting proof of self-hurt on the Snapchat application.
The Federal Bureau of Investigation (FBI) later let it be known didn’t as expected development on a clue about Mr Cruz the month prior to the shooting.
Large numbers of the shooting’s survivors proceeded to become conspicuous promoters for weapon enactment change and have requested that move be made to forestall comparative episodes.
How being an understudy weapon control dissident incurred significant damage
In an occasion denoting the third commemoration of the shooting in February, US President Joe Biden called for Congress to pass firearm law changes, remembering a boycott for attack weapons and a finish to lawful insusceptibility for firearm producers.
“We owe it to every one of those we’ve lost and to every one of those abandoned to lament to roll out an improvement,” Mr Biden said. “An opportunity to act is presently.”