Jared Loughner, 24, a college dropout with a history of psychiatric disorders, received seven consecutive life terms plus 140 years in prison, without the possibility of parole, under a plea deal with prosecutors that spares him the death penalty.
U.S. District Judge Larry Burns said the life sentences he imposed - one for each of the six people who lost their lives and a seventh for the attempted assassination of Giffords - represented the individuality of the victims.
"He will never have the opportunity to pick up a gun and do this again," Burns said.
Giffords suffered a head wound that left her with speech difficulties, a paralyzed right arm, diminished sight and a limp.
Addressing the court along with several survivors of the January 8, 2011, shooting, Giffords' husband, former astronaut Mark Kelly, told Loughner he had failed in his attempt to "extinguish the beauty of life".
Kelly used the occasion to take a political swipe at Arizona Governor Jan Brewer, a staunch gun-rights advocate, criticizing her for speaking out against proposed restrictions on high-capacity ammunition magazines, like the ones Loughner used, in the aftermath of the shooting.
"Jan Brewer said it had nothing to do with the size of the magazine. ... She said this just one week after you used a high-capacity magazine," Kelly said, also noting that she named a "state gun" weeks later instead of "fixing the education system."
Loughner, asked at the outset of the hearing by Burns if he had chosen to waive his right to make a statement, answered in a low voice, "That's true."
He was otherwise silent as he sat next to his lawyer, Judy Clarke, gazing expressionless at the survivors who spoke in court during the proceedings. He displayed no visible sign of emotion when he was sentenced.
Giffords stood by her husband's side, looking impassively at Loughner as Kelly addressed the defendant directly, in a clear, ringing voice. "You may have put a bullet through her head, but you haven't put a dent in her commitment to make the world a better place," Kelly told him.
"Although you were mentally ill, you were responsible," he added. "You have decades upon decades to contemplate what you did, but from this moment, Gabby and I are done thinking about you."
Giffords did not speak.
The proceedings marked a dramatic epilogue to a rampage of gun violence that shocked the nation, reignited a debate over control of firearms and cut short the political career of a rising star in the Democratic Party.