With his squinty eyes, baby face, and big build, Kevin Lacz sort of resembles tough guy actor Tom Hardy. Perhaps it’s why director Clint Eastwood and star Bradley Cooper felt Lacz should play himself, a fellow Navy SEAL in Chris Kyle’s unit, in the Hollywood blockbuster American Sniper. The film has, of course, become a bona fide phenomenon, grossing close to $300 million stateside and receiving 6 Oscar nominations, including Best Picture.

But Kevin Lacz is no actor. He enlisted in the Navy SEALs in 2002, following the death of his friend’s father during 9/11, and served two tours in Iraq in 2006 and 2008. There, he did two platoons at SEAL Team 3 (Charlie and Delta) where he worked as a sniper alongside Chris Kyle, who became a mentor and good pal.

His involvement in American Sniper dates back to 2010 when Kyle rang him up asking if Jim DeFelice could interview him for his book of the same name. He obliged. Two years later, the film adaptation of the book was being set up and Lacz’s wife reached out to Jason Hall, the film’s screenwriter, over Facebook to tell him to “do the story justice.” He replied, “Well, help me do it then.” She put him in touch with Lacz, who advised him on technical matters for the script—guns, the art of being a sniper, direct action missions. Hall finished the script and one day later, Kyle was murdered. Lacz invited Hall down to Kyle’s memorial service in Texas, and served as a liaison between him and Kyle’s fellow SEALs.

Sniper producers Rob Lorenz and Andrew Lazar eventually hired Lacz as a technical adviser on the film, and he met up with Bradley Cooper at the shooting range in February 2014. About two hours into the shoot, Cooper looked up from his gun and said to him, “Hey, did you ever think about playing yourself in the movie?” Lacz was speechless.

Cooper convinced Eastwood to let him audition, and he tried out for the role of a contractor who gets shot on the side of the road, and playing himself—or “Dauber,” his SEAL nickname. Lacz shot an audition tape in his wife’s great aunt’s kitchen in Vermont, and sent it over to Eastwood. The grizzled filmmaker came back with a message he’ll never forget: “The boy’s damn good! Get him the job.” 

THE DAILY BEAST: Do you remember the first time you met Chris Kyle?

KEVIN LACZ: I had gotten to SEAL Team 3 and the guys hadn’t come back yet. You started to hear guys were doing good things overseas, and there was a guy who’d had 20 some-odd kills in Fallujah, and it was Chris. It started painting the picture of a guy who was setting himself apart. He was called “Tex” back then, but then people started joking around and calling him “The Legend” because he was pretty legendary in Ramadi.

But the first time I met Chris, I just walked into the platoon space and that’s how I got my nickname “Dauber.” My LPO was there and Chris was there, and I had ambled in—and had more blond hair back then—and they just said, “Dauber.” I was like, “What the fuck does that mean?” I guess it was from Coach. It could’ve been worse. Chris was older, too, so we’d joke around and call him “Old Balls” every now and again, and then he’d choke you out and shit. But with Chris, as a new sniper in the platoon, you study the people you work with because you want to be at that level, and Chris was someone I studied, and who was a mentor to me.

"Men and women in the military know what’s really going to hurt them, and it’s not comments. It’s RPGs and bullets."

What about him made him become the “deadliest sniper in U.S. history?”

The dedication. He had this uncanny ability to just sit on that scope and have this situational awareness of what’s going on. In the movie they show deliberate guys planting IEDs, but in real life, it’s a little bit more inconspicuous. You have to be watching at all times because it can just be a quick flash. Chris was just focused. He’d be the first one to tell you he wasn’t the best shot in the world, but he had more dedication.