Erin Nealy Cox is talking about her daughter’s cellphone while eating a seared tuna salad at Ocean Prime. “We wring our hands constantly,” Cox says of the decision to let her oldest have a phone. “When is the right time to introduce a cellphone? What are they allowed to do? If your child is not getting a phone during middle school, they’re going to be one of very few.”

So when Cox and husband Trey gave in to 11-year-old Amelia’s request for a phone, they drew up a contract. Some of the rules include no texting after 9 pm, that Amelia check in the phone nightly, and that she maintain an A in all her classes or lose phone privileges. “She doesn’t understand all the implications of the rules now, but whenever something comes up, I try to educate her.”

Cox has good reason to be concerned about her daughter’s foray into technology. As the executive managing director at Stroz Friedberg, a firm that specializes in digital risk management and cybersecurity, she spends her days helping companies overcome cyberattacks from hackers. “We bring our technical forensic team to the company, and we collaborate with their general counsel office, IT security office, and C-level officers to understand what happened.” And then they counsel the company. “We understand there is a way out of the darkness,” she says.

Cox, a former prosecutor who met her husband while clerking on the Fifth Circuit, is the only woman running offices at Stroz Friedberg, overseeing Dallas, Chicago, and Minneapolis. And she has three daughters: Amelia, 7-year-old Cate, and 2-year-old Vivian.

If you didn’t know better, you might be intimidated by Cox. Even at 5 feet 8 inches tall, she always wears heels—and she commands respect. But then her face lights up as she talks about Cate aging her nine years. “Are you kidding me? You clearly have no idea how old your mother is,” the 43-year-old remembers saying. Suddenly, you realize she is human after all—just a really organized, powerful, passionate human raising three kids in the Park Cities.

KN: In 2003, you were working as a federal prosecutor in the Dallas U.S. Attorney’s office and raising your 1-year-old with your husband. Then you changed gears completely. What happened?

ENC: I got an opportunity during the Bush administration to go work for what was at the time called the Office of Legal Policy. It was this small division within the Department of Justice devoted to high-priority policy initiatives. Our job was to coordinate between the White House Counsel’s office and the Senate Judiciary Committee, and so it was a really interesting mix of policy and legislative work. That division was filled with super smart people working on issues right after 9/11. It was just an incredible opportunity. Amelia turned 2 in December, and we were on a plane to D.C. in January. I just couldn’t bear the thought of leaving her at home. You have to sort of do that analysis. I remember talking with my soon-to-be boss. “Look, I’ve heard about this section. You guys are working till midnight, 2 o’clock in the morning. These issues are not issues that can wait. If you need me to be at my desk, I’m not going to be able to do it.” He was so great and forward-thinking and was like, “Let’s try it.” He gave me the opportunity, even though he knew what my challenges were. That is a special boss.

And so we went up there. My husband was flying up and back every weekend. We got Amelia into a nursery school we could walk to. I would drop her off, go to work, pick her up at 6:15 every day, and carve out a couple of hours that were Amelia time. At 8:15, I was back at my computer until midnight or 2 o’clock in the morning. That was our life for 18 months. During that time, I was promoted to chief of staff and worked on all these great things. We did it for as long as we could do it. [Laughs.] At some point, you have to say, “Okay, this is amazing, but I’ve got to get back to a more normal lifestyle.”

KN: Would you do it again?

ENC: Oh my gosh. Who knows? I never say never. It was so challenging. I look at Vivian, and she’s 2. I think the reason I was able to convince myself that I could do it was because I didn’t know better. [Laughs.]

KN: So you were, and still are, living the life that Sheryl Sandberg writes about in her book, Lean In, which discusses women at work and gender roles in the workplace. What advice do you have for other women trying to balance work and family?

ENC: You should try to follow every dream you have, but you have to make practical choices given your family situation. I’m raising girls, and I want to be one of many role models they have in life. You can make these tough choices. You can have a life so full, so great, and not to the exclusion of everything else.

KN: There’s a shortage of women in STEM (science, technology, engineering, and mathematics) fields right now. Is that something you will encourage your daughters to look into?

ENC: I’m pushing my girls toward math and science. Not only are STEM jobs important for our economy, but they’re important for women. If you’re a woman in a STEM job, you have the golden ticket. I signed all three of my girls up for camps at the Perot Museum this summer. I talk about how math is for awesome people. That’s not my background, but I can see that is the future. There are definitely not enough women. I see it all the time in my business. I am the only woman running an office in my firm. I’m in conference rooms and boardrooms all the time, and they’re male-dominated. I’m fine with that. I’m comfortable with it. But we need to get more women in those boardrooms.

KN: How do we do that?

ENC: That’s the million-dollar question. We’ve got to have bosses like my current boss. Like my boss in D.C. They were willing to see a person who had small children but knew that didn’t mean she couldn’t do quality work. We have to have people who will give women chances. And we have to have women who don’t take themselves out of the game.