US Army veteran Chris Mintz started his day on Thursday heading to class at Umqua Community College, excited about marking his son’s sixth birthday.
But hours later, in an attempt to charge the gunman, he was shot five times.
The 30-year-old is now in hospital and could make a full recovery, according to a Facebook post by his cousin.
Shortly after shooting Mr Mintz, gunman Chris Harper Mercer was killed in a shootout with police.
The gunman entered a classroom in the rural community college’s Snyder Hall, reportedly asking students if they were Christian before shooting.
The Army veteran rushed the gunman to try to stop him, his family told CBS This Morning.
Mr Mintz first blocked the door to try to prevent the gunman from getting in the classroom, and was then shot three times.
He hit the floor, told the gunman it was his son Tyrik’s sixth birthday, and was shot twice more.
Surviving the attack, he spent most of Thursday in surgery at Mercy Medical Center in Roseburg, where he is stable.
“He’s going to have to learn to walk again, but he walked away with his life,” one family member said.
Mr Mintz’s cousin Derek Bourgeois described the scene in a Facebook post, saying he “took five shots on his son’s birthday.”
People flooded Mr Bourgeois’ Facebook post with words of support and encouragement for Mr Mintz, calling him a “hometown hero” and a “legend” and asking if they could visit him in the hospital or start funds for his medical bills.
“You saved lives Chris Mintz. You are the one who will be remembered. You are a hero in my eyes with a warrior’s spirit. God bless you and your recovery,” one person wrote.
He had just written on his Facebook past midnight on Wednesday, “Happy Birthday Tyrik.”