Hatley and his wife, who sat behind him in the public gallery, both showed no emotion when the sentence was read out.
The career soldier had urged the eight-member military jury to let him complete six more months of military service, which would have brought his total service to 20 years.
He said: "I've served my country for half my life, which I think is the most honourable profession in the world.
"I served America with the best men our great country has to offer. And they are so many. My soldiers are like my sons and there's nothing I wouldn't do for them."
John Riesenberg, the prosecution lawyer, had argued the case was about how Hatley used his reputation to lead his soldiers "down the brutal path to murder".
"This is among the most colossal failures of leadership," Riesenberg said.
Hatley could yet have his time in prison reduced by the army's convening authority, a military panel that will review the case and sentence.
Army rulings also go through an automatic appeals process.
On Wednesday, the jury had found Hatley guilty of premeditated murder and conspiracy to commit premeditated murder after a three-day trial.
Hatley, 40, was acquitted of another murder in January 2007 of an Iraqi opposition fighter, who medics said was shot when already close to death.
The incident for which Hatley was convicted occurred in March or April 2007, when Hatley's unit had exchanged fired with a group of four Iraqis.
Weapons were then found in a building the four had fled to, and the men were taken into custody.
Hatley was accused of overseeing the shootings of the detainees and telling his colleagues that they were to "take care" of them and kill them.
The defence asserted that there was no physical evidence of the deaths as no bodies, witnesses or blood have been found.
Hatley was the highest ranking of three soldiers tried for killing the prisoners, the other two were convicted of the murders separately earlier this year.
Two other soldiers were also convicted of involvement in the spring 2007 incident.
All were with the 1st battalion, 18th infantry regiment, 2nd brigade, 1st infantry division in Baghdad. The unit is now part of the Germany-based 172nd infantry brigade.
Hatley had previously served in the first Gulf War and Kosovo.