Giffords, who nearly died when she was shot in the head from close range in the shooting spree at a constituents meet-and-greet outside a supermarket, drew cheers and gasps from those on hand as she walked deliberately across the stage with occasional assistance from her chief of staff, Ron Barber, The New York Times reported. Barber also was among the 19 people wounded or slain that day one year ago.
Wearing a bright red scarf, Giffords spoke clearly and held her right arm with her left hand as she spoke, culminating with a big smile to the audience before leaving the stage, the newspaper said.
The vigil was not only to mark the tragedy but to show the way forward for the community.
"We refuse to let this tragic day define us," Patricia Maisch, one those who grabbed the gun from the shooter, said at a memorial service Sunday.
President Obama called Giffords early Sunday to offer his support, saying he and the first lady keep her, the families of the fallen and the Tucson community in their thoughts and prayers, the White House said.
Obama also praised Giffords for the courage and determination she has shown in the wake of her injury, calling her an inspiration.
The father of one of those killed says his son's heroism during the attack may be marked by a memorial bench.
Ross Zimmerman told The Arizona Republic he hopes people think of his son while hiking above Davidson Canyon where a bench engraved with his son Gabe's name might be erected.
Gabe Zimmerman, was Giffords' aide.
Workers at Giffords' offices told Ross his son was probably trying to help save others when the shooting started, the Republic reported Sunday.
"Gabe was down the line a ways, and for him to have been where he was when he got shot, he had to have sprinted [toward the shooting]," Ross said.
"Back into the middle of things to try and help. And he died in the attempt."
Jared Loughner, 23, has been charged in the shooting spree in which six people died. He suffers from schizophrenia and has been fighting a court order to keep him on anti-psychotic medication. He is being held at the federal mental hospital in Springfield, Mo.