A 74-year-old retired Army colonel decided to tackle the Tucson gunman after watching him shoot a little girl.
"Something had to be done," Bill Badger said today on "Good Morning America."
Badger wasn't the only one who risked his life to stop the carnage. One man clobbered alleged gunman Jared Loughner on the back of the head with a folding chair. A 61-year-old woman wrestled a fresh magazine away from Loughner as he tried to reload.
Others jumped on him and held him down, ripping the gun from his hands.
Six people were killed in Saturday's shooting rampage at the Tucson, Ariz., grocery store, and Rep.Gabrielle Giffords was left fighting for her life.
Badger was waiting in line to meet Giffords at the "Congress on Your Corner" event when he heard gun shots.
"I turned and dropped to the ground, and I felt a sting in the back of the head, and that's where he shot me, in the back of the head. I knew I'd been hit," Badger said.
Badger, who was treated for the injury at the University Medical Center and released, is among those who've been hailed as heroes for subduing Loughner and stopping further carnage after a shooting that left 20 people shot or injured.
"[Loughner] was standing right in front of me. He took about a half a step to my left and some individual there took one of the folding chairs ... and hit him on the back of the head, and I was able to grab him," Badger said.
Together, Badger and another man pushed the suspected shooter to the ground.
Patricia Maisch, 61, was in the back of the line, waiting to greet and take a photo with Giffords. When she heard gun shots, she hit the ground.
"I'm waiting to be shot because the lady next to me had been shot," Maisch said. "At the same time, someone says, 'Get the magazine.'"
Loughner allegedly used a legally purchased Glock 19-9 mm gun with an extended magazine to carry out the shootings.
Maisch grabbed the second magazine that Loughner was attempting to load into the gun.
Badger then helped tackle Loughner. Badger and Roger Salzgeber, who was reportedly standing with his wife, third in line to meet with Giffords, sat on the gunman while Maisch held his ankles down.
"When we pushed him to the ground, there was no struggle and no fight," Badger said. "I had this guy by the throat ... in a chokehold."
Salzgeber isn't ready to comment on his role in stopping the gunman, saying that he's still "dealing with it all."
Joseph Zamudio was at a nearby Walgreens when he heard the ring of gunshots.
"I heard the gunshots and came running," Zamudio said on "GMA."
Zamudio helped restrain Loughner by hanging onto his legs.
Another individual grabbed the gun from Loughner, Badger said.
As Badger was tackling the man spraying bullets at innocent bystanders, Badger's wife was frantically calling 911, seeking information about her husband.
"My husband just called me and told me he was shot. He was going to the Gabrielle Gifford event, and I don't know where he is," Badger told 911. "He called me and then the phone went dead."
Badger's 911 call was one of several that even left operators losing their composure.
"Oh my God," exclaimed a 911 operator who got the first report of the carnage.
Badger was among those struggling, according to Maisch. When she noticed the blood coming from the back of his head, she asked Zimude to hold down the shooter while she went to get paper towels and made a compress.
Maisch was thankful for the heroic actions of Badger and others at the scene.
"He saved my life," she told "GMA."
"Those two gentlemen saved my life."
Pima County Sheriff Clarence Dupnik lauded the actions of Maisch and others that he said likely saved dozens of lives.
"We could have had 31 more people shot," Dupnik said.
One of Congresswoman Giffords' interns, 20-year-old Daniel Hernandez, has been credited with helping keep Giffords alive after she was shot in the head.
"When I heard gunshots, my first instinct was to head toward the congresswoman to make sure that she was okay," Hernandez told Amanpour. "Once I saw that she was down and there were more than one victim, I went ahead and started doing the limited triage that I could with what I had."
Hernandez held Giffords, applying pressure to her wound. He used smocks from the grocery store as a bandage.
"The congresswoman was alert. She was able to hold my hand when I asked her if she could hear me," Hernendez said. "I wasn't able to get any words from her. She may have been trying, but because of the way that I was having to hold her it was a lot easier to just 'if you can hear me Gabby just grab my hand to let me know that you're okay.'"
Giffords remains in critical condition in a medically induced coma with part of her skull removed to ease pressure on her brain.
Loughner has been charged with multiple counts of murder and attempted murder. He will make his first court appearance later today.