The guy who went viral for jumping through an In-N-Out drive-thru window to confront an armed woman says he had another mission in mind ... defending Gen Z.

Luca Opperman, a 20-year-old former gymnast, chatted with Harvey and said he was in the drive-thru with his girlfriend when he spotted the woman swinging around a roughly five-foot stick.

He tells us he initially wasn't planning to get involved ... but that changed when she opened a gate and started heading toward employees in the kitchen.

That's when Luca climbed through the drive-thru window, grabbed a spatula, and stepped in.

He eventually managed to wrestle the stick away from her ... after yelling at two older guys nearby for just sitting there and watching.

Luca says part of what pushed him to act was the whole narrative that Gen Z is soft ... telling Harvey he wanted to prove otherwise.

Harvey told him he's basically the poster boy for Gen Z now.

Luca's heroics didn't go unnoticed by In-N-Out either ... he tells us the company's COO personally reached out to thank him and hinted that some goodies may be coming his way.

Luca tells us he'd be happy with a gift card ... because the only thing better than In-N-Out is free In-N-Out.