Matt McQuinn died trying to protect his girlfriend.
As a gunman fired on moviegoers at an Aurora movie theater, McQuinn dove on top of Samantha Yowler.
The 27-year-old Ohio native had moved to Colorado in November.
McQuinn's stepfather, David Jackson, told the Dayton Daily News that McQuinn was a hero.
"Him and Sam were very much in love and planning their life together it's not surprising to me that his first thought would be her. That's what a man does. He protects his loved ones. I'm very proud of him. I'm going to miss him," Jackson said.
"He was probably scared, terrified," said Jackson. "I just can't imagine what would be going through his mind except saving Sam. Im sure from his actions that he didn't put anything except for her first. Other than that, how could you not be terrified in a situation like that? I just hope it was quick."
Yowler was injured in the leg, a family spokesman said.
Her brother, Nick, was in the theater as well, but was not injured.
Rob Scott, attorney for the McQuinn and Yowler families, said McQuinn was shot three times -- in the chest, leg and back.
"Matt was a fun-loving guy," said Mitch Sprinkle, a 24-year-old Springfield resident and friend of McQuinn. "Everyone that I've introduced him to loved him off the bat. He had a really great heart and personality. Hes one of those people that instilled you with positivity."
Long-time friend Nicholas Gill said McQuinn and his girlfriend were known for their elaborate Halloween costumes for a friend's annual party.
"Matt was a fun-loving guy," Mitch Sprinkle, a 24-year-old Springfield resident and friend of McQuinn told the Daily News. "Everyone that I've introduced him to loved him off the bat. He had a really great heart and personality. He's one of those people that instilled you with positivity."