Mourners packed a church in this western Ohio town where McQuinn was from, the same morning that others came together in San Antonio to remember another shooting victim, 24-year-old Jessica Ghawi. Other victims' funerals were held earlier this week, and more are set for next week.
When gunfire broke out in the Aurora, Colo., theater, McQuinn, 27, dove in front of his girlfriend, Samantha Yowler, and was shot three times.
Yowler, who was shot in the knee and survived, arrived at McQuinn's funeral on crutches Saturday and wept quietly with his parents and other family during the funeral. Neither she nor his parents addressed Maiden Lane Church of God.
"Matt's death is a sudden loss, one that has produced many questions in your minds," Pastor Dan Fiorini said. "I know you're asking in your heart of hearts, why? Why was Matt there? Why was a gunman allowed to enter that theater? Why was he able to purchase guns and ammunition so easily? Why didn't God do something?"
Fiorini said he couldn't answer any of those questions.
"We can wrestle with the whys of this tragedy for eternity and never come up with an answer," he said.
Pastor Herb Shaffer, who's also McQuinn's uncle, told mourners that the shooting forever changed them.
"Our lives will never be the same," he said. "The words Aurora, Cinema 16 shooting, Batman, will never mean the same thing, and we'll be reminded of Matt every time we hear them."
He said McQuinn had been a gift to his family since he was born and that his actions in Colorado were just one example of his selflessness.
He spoke of how McQuinn called his mother three times the day before she had surgery because he was upset that he couldn't be there in person and wanted to make sure she was OK.
When McQuinn was just 7, Shaffer said, he was once so concerned that his younger cousin wasn't having a good day and put his arm around her to try to make her feel better.
He spoke of McQuinn's greatest sacrifice of all, saving Yowler, whom Shaffer described as his nephew's best friend and the love of his life.
"In moments of crisis, true character comes out," he said. "His immediate response was to protect the woman he loved."
At Jessica Ghawi's funeral in her hometown of San Antonio, mourners focused their remarks on the aspiring sports journalist's energy and life.
"What we will not do today is focus on how she left us," said Peter Burns, a friend from Colorado. "Jess was a force to be reckoned with. She was a jolt of lightning. A whirlwind. A Labrador puppy running clumsily with innocent joy."
Burns talked of the funny way Ghawi sneezed, her near-addiction to Nutella, how she was sloppy and always lovable.
Ghawi's boyfriend, Jay Meloff, note that others described her as "a tough, redheaded spitfire," and she was, but that he also saw "a beautiful, warm-hearted and passionate woman with a capacity for love. ... She was as mushy as they come."
He said they were looking forward to building a future together and he also encouraged others to do as she did and "live each day fully."
"She drank in life," he said.
Her mother said that those who didn't know Ghawi missed out.
"Those of you who knew Jessie were absolutely blessed," she said. "She lived fiercely and loved deeply and crammed more into her 24 years of life than most of us do in a lifetime."
Ghawi was a pretty, blue-eyed redhead who moved to Colorado about a year ago. She had survived a June 2 shooting at a Toronto mall that left two dead and several wounded. She blogged about the experience, writing that it reminded her "how fragile life was."
"I was reminded that we don't know when or where our time on Earth will end. When or where we will breathe our last breath," Ghawi wrote.
James Holmes, a 24-year-old former doctoral student studying neuroscience, is accused of opening fire on the theater, killing McQuinn, Ghawi and 10 others, and wounding 58. He is due to be formally charged Monday in Colorado.
Associated Press writer Linda Stewart Ball in Dallas contributed to this report.