As the gunman strafed the crowd from his Mandalay Bay suite, Las Vegas native McInerney laid on top of his girlfriend, Alyssa, to shield her from the ammunition.
The pair made their escape from the horrific scene on that dreadful October night, but as the gunfire continued McInerney jumped into his truck, parked nearby, and drove others to safety.
It is for that act of courage that the 24-year-old has been rewarded with a sponsors invitation to a PGA Tour event in his home city.
In his Tour debut, McInerney will compete at the Shriners Hospital for Children Open, which starts Thursday at TPC Summerlin, against the likes of former Masters champion Bubba Watson and Presidents Cup team member Charley Hoffman.
On Twitter, after the horrific incident, McInerney tweeted that he was "lucky to be alive" and "praying for everyone."
In another post, he tweeted: "If anyone needs something, I can help in any way possible right now. #vegasstrong."
'A crazy mess'
"It was a crazy mess. It was so gruesome to see," McInerney -- who finished No. 97 on the 2017 Web.com Tour money list as a rookie -- told the Golf Channel days after the mass shooting.
"We could hear the bullets hitting the ground next to us. We could see the spark and the smoke. You could hear that thump of a bullet hitting somebody. When you're running through that, you're praying. You're just trying to get as far away as you can."
McInerney said playing a PGA Tour event in his home city "means the world to me."
"To have this opportunity this week in my hometown where I was born and raised is something I have been looking forward to since I was 15 or 16 years old," McInerney told reporters Monday.
"In the midst of everything that has happened over the last month or so, to get the chance to play here, and kind of play for Las Vegas, and to see all these people out here in the Vegas community come together, it's an opportunity I'll never forget, for sure."