KILLEEN, Texas — Maj. Nidal Malik Hasan, the Army psychiatrist who admitted to killing 13 unarmed people at Fort Hood nearly four years ago, was sentenced to death by lethal injection by a jury on Wednesday, becoming one of only a handful of men on military death row.

Since the case against Hasan was overwhelming, his conviction was a near certainty, and the main question in the trial was whether he would receive the death penalty.

Prosecutors had from the start built a case for execution for an attack that a Senate report called the worst act of terrorism on U.S. soil since Sept. 11, 2001. But Hasan, a Muslim, taunted the military justice system, refusing to put up a defense and suggesting in and out of court that death to him was but a means to martyrdom, leaving jurors to ponder whether to give him what he wanted.

His stance left the Army’s lead prosecutor, Col. Michael Mulligan, telling jurors during his closing argument on Wednesday morning that Hasan was not and never would be a martyr.

“Do not be fooled,” he told the 13 senior officers on the panel. “He is not giving his life. We are taking his life. This is not his gift to God. This is his debt to society.”

The jurors took a little more than two hours decide the sentence. If even one of them had objected to Hasan’s execution, he would have been sentenced to life in prison. The same jury on Friday found Hasan guilty of 45 counts of murder and attempted murder.

Because of the high profile and heavy toll of the Nov. 5, 2009, attack — more than 40 people were killed or wounded — Hasan is likely to become the first U.S. soldier in more than half a century to be executed in the military’s death chamber at Fort Leavenworth, Kan. The execution would require presidential approval.

Driven, he said, by a hatred of U.S. military action in the Muslim world and a desire to protect Taliban leaders in Afghanistan, Hasan fired 146 rounds at men and women as they crawled on the floor or crouched behind desks and cubicles, he killed 12 soldiers and a civilian who lunged at him with a chair.

If Hasan, who will soon turn 43, is executed, it will probably not be for 10 or 15 years.

Some military legal experts suggested that Hasan’s case — in which he became a nonparticipant at his own trial and sought the death sentence — represented a fundamental breakdown of the military justice system. Others disputed that assertion.

Hasan was found competent to stand trial, and the judge, Col. Tara Osborn, who repeatedly told him it was unwise to proceed on his own, said his right to represent himself allowed him to be, as she put it, “the captain of his own ship.”