GARLAND, Texas (CBSDFW.COM) – It could have been a North Texas massacre with up to 150 victims, if not for a Garland Police officer who became the first lawman in the country to engage ISIS-inspired terrorists on Texas soil.

Greg Stevens, now 63, has lived for four years on terrorist hit lists and shadowed by national intelligence.

Greg Stevens – retired Garland Police officer (CBS 11)

Stevens has also received the nation’s highest law enforcement honor and is revealing himself publicly for the first time.

“They kept me out of the media and kept my name and so on anonymous for a long, long time,” said Stevens.

Four years ago this month, on May 3, 2015, he singlehandedly stopped an ISIS terrorist attack as a Garland Police officer.

Stevens was one of 40 officers assigned to security detail at the Curtis Culwell Center that Sunday in Garland.

It’s where a conservative group hosted a Muhammad cartoon contest that authorities knew would likely anger some Muslims.

“This had a lot of potential for bad things happening,” said Stevens.

Elton Simpson and Nadir Soofi drove from Arizona with guns on an ISIS inspired mission authorities say to kill the 150 people attending the event.

GARLAND, TX – MAY 4, 2015 : Members of the FBI Evidence Response Team investigate the crime scene outside of the Curtis Culwell Center after a shooting occurred the day before, on May 04, 2015 in Garland, Texas. (Photo by Ben Torres/Getty Images)

“This little black car came from my left as I’m facing out on the street,” said Stevens.

Stevens believes the two attackers chose to pull up at the entrance monitored by him and an unarmed Garland ISD officer.

“They probably looked over there, look there’s two guys, one of them is not even armed, the other guys 100 years old how hard can this be? The next thing I see is somebody dressed in all black stepping out of the car and the barrel of a rifle coming up in my direction.”

Stevens fired 14 rounds from a handgun while the two men with rifles fired 35, one of them, striking unarmed security guard Bruce Joiner in the leg.

Within seconds, the veteran officer took down the gunmen from more than 30 feet away.

“This whole event probably didn’t take no more than 10 and probably 15 seconds,” said Stevens. “I’m a pretty good shooter. I’m not a great shooter. My training kicked in. I wasn’t formulating a plan.”

Even with the terrorists on the ground, Stevens worried one of them was wearing an explosive.

“It looked to me like he was trying to push a button or pull a pin. Shooting an old traffic cop wasn’t what they were there for. They had bigger plans.”

Those plans ended in the parking lot with the deaths of two men Stevens still feels compassion for.

“It’s unfortunate these young men were willing to sacrifice their life over something I don’t understand,” Stevens said. “It is a great loss. It is a tragedy.”

President Obama awarded Stevens the Medal of Valor for his bravery, a moment that still makes this rugged cop misty-eyed.

“What a great thrill that was what a gift to be able to give your 17-year-old son an opportunity to shake hands with the leader of the free world,” he said.

Stephens lives now as a private citizen but chooses not to worry about being a target of other terrorists.

“My name is on probably a couple of lists that you probably don’t want to be on.”

Four years after the Garland attack, it’s become a footnote in history because of the one man who foiled it.

“It could’ve been disastrous as far as loss of life and injury.”

Stevens credits his fellow SWAT officers with coming to his assistance almost immediately after the shooting and securing the scene.

After serving 40 years on the force, Stevens turned in his badge in August 2018.

He currently works with Sheepdog Seminars.

It’s a safety training organization that helps churches and faith based religious groups combat violence. Stevens is also working with F.O.R.G.E. Resilience which provides stress training for first responders.

Stevens is speaking out because he wants to promote the importance of police training for situations like this and currently runs church safety seminars.