Authorities say a man in the audience was killed trying to protect his family during an attempted assassination of Donald Trump on Saturday.
Corey Comperatore, a 50-year-old volunteer fire captain, rushed to save family members when the shots rang out.
“Corey died a hero,” Pennsylvania Gov. Josh Shapiro said at a news conference on Sunday.
Pennsylvania State Police said the other two people shot were David Dutch, 57, and James Copenhaver, 74. Both were in stable condition Sunday.
Pennsylvania’s governor said he had spoken with Mr. Comperatore’s wife and two daughters.
“Corey went to church every Sunday,” he said. “Corey loved his community. Most importantly, Corey loved his family.”
He said Mr Comperatore was a staunch supporter of Donald Trump and was excited to attend the rally on Saturday.
“Corey was the best of us. May his memory be a blessing,” Shapiro said. “Last night was horrifying… political differences can never, ever be resolved through violence.”
Mr Comperatore’s daughter, Allyson, described him as “the best dad a girl could ask for” and said he had “gone like a real-life superhero”.
“He wrestled my mother and I to the ground… [and] shielded my body from the bullets that were fired at us,” she wrote on Facebook.
His wife, Helen Comperatore, added: “What my precious daughters had to witness was inexcusable.”
A GoFundMe set up for the family has raised more than $830,000.
State police said Mr. Comperatore lived in Sarver, about 12 miles (19km) from the protest site in Butler, outside Pittsburgh, Pennsylvania.
Firefighters at the Buffalo Township Volunteer Fire Department in Butler held a memorial service for Comperatore, where his firefighting gear was draped in black and put on display.
“He was a great man who deserves the highest honor and respect,” said Craig Cirrincione, a firefighter who attended the memorial service.
“He doesn’t want us to sit here and be sad… He wants us to share the good times and think about him.”
Randy Reamer, president of the fire company, said Mr Comperatore was a “man of integrity” and “a true brother to the fire service”.
“He certainly stood up for what he believed in and never backed down from anyone,” he said.
According to his social media profile, in addition to volunteer firefighting, Mr. Comperatore is also employed as a project engineer and processor at a plastics manufacturing company.
“He was a good guy,” neighbor Matt Achilles told Pittsburgh Tribune-Review“We may not have agreed on the same political views, but that didn’t stop him from being a good friend and neighbor.”
“He donated money to us when I was in the hospital and he would always stop by our yard sales. He would always wave when I drove by his house,” said Mr. Achilles.
Paul Hayden, 62, a neighbour of Mr Comperatore’s for 20 years, described him as an “easy-going guy” and said political differences did not hinder their friendship.
“He knows I’m a Biden fan, I know he is. [was] “I’m a Trump fan,” Hayden told NBC News. “But we never let that get between us. We still say hello, we still talk to each other. Some people take it too far.”
Mr. Shapiro also said he spoke with the family of one of the injured, but declined to provide details of the conversation.
A bullet, one of six to eight shots fired at the protest, grazed former President Trump’s ear.
The gunman, identified by authorities as Thomas Matthew Crooks, 20, was shot dead by Secret Service officers tasked with protecting the former president.
