The rare military death sentence came nearly four years after the attack that stunned even an Army hardened by more than a decade of constant war. Hasan walked into a medical building where soldiers were getting medical checkups, shouted "Allahu akbar" - Arabic for "God is great!" - and opened fire with a laser-sighted handgun. Thirteen people were killed.
Hasan, who said he acted to protect Islamic insurgents abroad from American aggression, had no visible reaction when the sentence was announced, staring first at the jury forewoman and then at the judge. Some victims' relatives were in the courtroom but none showed any reaction, which the judge had warned against.
The American-born Muslim of Palestinian descent never denied his actions at the huge Texas Army post. In opening statements, he told jurors that evidence would show he was the shooter and described himself as a soldier who had "switched sides."
The same jurors who convicted Hasan last week needed to agree unanimously on a death sentence. The only alternative was life in prison without parole.
Kathy Platoni, an Army reservist who still struggles with images of Capt. John Gaffaney bleeding to death at her feet, said she was not opposed to the punishment.
Hasan wanted "to be a martyr and so many of the (victims') families had spoken to the issue of not giving him what he wants because this is his own personal holy war," said Platoni, who watched most of the trial from inside the courtroom.
"But on the other hand - this is from the bottom of my heart - he doesn't deserve to live," she said. "I don't know how long it takes for a death sentence to be carried out, but the world will be a better place without him."
Hasan could become the first American soldier executed in more than half a century. But because the military justice system requires a lengthy appeals process, years or even decades could pass before he is put to death.
He was expected to be taken on the next available flight to the military prison at Fort Leavenworth in Kansas.
In his final plea for a death sentence, the lead prosecutor assured jurors that Hasan would "never be a martyr" despite his attempt to tie the attack to religion.
"He is a criminal. He is a cold-blooded murderer," Col. Mike Mulligan said. "This is not his gift to God. This is his debt to society. This is the cost of his murderous rampage."
Since the attack, the federal government has sought to execute Hasan, believing that any sentence short of a lethal injection would deny justice to the families of the dead and the survivors who had believed they were safe behind the gates of Fort Hood, about 70 miles north of Austin.
And for just as long, Hasan seemed content to go to the death chamber for his beliefs. He fired his own attorneys to represent himself, barely mounted a defense during the three-week trial and made almost no effort to have his life spared.
Mulligan reminded the jury that Hasan was a trained doctor yet opened fire on defenseless comrades. Hasan "only dealt death," the prosecutor said, so the only appropriate sentence was death.
Hasan was never allowed to argue in front of the jury that the shooting was necessary to protect Islamic and Taliban leaders. But during the trial, he leaked documents to journalists that revealed he told military mental health workers in 2010 that he could "still be a martyr" if executed by the government.
When Hasan began shooting, soldiers were standing in long lines inside a medical building to receive immunizations and doctors' clearance. Many of the soldiers were preparing to deploy, while others had recently returned home.
All but one of the dead were soldiers, including a pregnant private who curled on the floor and pleaded for her unborn child's life. More than 30 other people were wounded.
The attack ended when Hasan was shot in the back. He is now paralyzed from the waist down and uses a wheelchair.
The military called nearly 90 witnesses at the trial and more during the sentencing phase. But Hasan rested his case without calling a single person to testify and made no closing argument. Even with his life at stake during the sentencing phase, he made no attempt to question witnesses and gave no final statement to jurors.
Hasan's civil attorney, John Galligan, said Wednesday that he believes Hasan received an unfair trial. Galligan said he was disappointed in the sentence and was confident it would be reversed on appeal.
Death sentences are unusual in the military, which has just five other prisoners on death row. Of 16 death sentences handed down by military juries in the last 30 years, 11 have been overturned, according to an academic study and court records. No American soldier has been executed since 1961.
Eduardo Caraveo, whose father was killed in the rampage, said he cared more about Hasan being convicted than about the sentencing. But he would have preferred that Hasan receive a life sentence.
"I didn't want him getting any satisfaction, so him getting killed by the government just gives him what he wanted. .... to be a martyr," said Caraveo, who lives in Tucson, Ariz. "My main thing is him being held accountable for his action. That's really all I ever wanted."
Authorities said Hasan spent weeks planning the Nov. 5, 2009, attack, including buying a handgun and videotaping a sales clerk showing him how to change the magazine.
He later plunked down $10 at a gun range outside Austin and asked for pointers on how to reload with speed and precision. An instructor said he told Hasan to practice while watching television or sitting on his couch with the lights off.
When the time came, Hasan stuffed paper towels in the pockets of his cargo pants to muffle the rattling of extra ammunition and avoid arousing suspicion. Soldiers testified that Hasan's rapid reloading made it all but impossible to stop him. Investigators recovered 146 shell casings in the medical building and dozens more outside, where Hasan shot at the backs of soldiers fleeing toward the parking lot.
In court, Hasan never played the role of an angry extremist. He didn't get agitated or raise his voice. He addressed the judge as "ma'am" and occasionally whispered "thank you" when prosecutors, in accordance with the rules of evidence, handed Hasan red pill bottles that rattled with bullet fragments removed from those who were shot.
Associated Press writers Will Weissert at Fort Hood and Ramit Plushnick-Masti in Houston contributed to this report.