“You make sure people are hearing that from every level of the organization and you live it every day,” Nye tells Fortune. “Living it, not talking about it, is what really makes the big difference.”

Nye has been working in the construction business for more than three decades and since 2010 has been CEO of Martin Marietta (MLM). A lawyer by background, he looks the part of a successful and imposing business leader. But talk to him for a few minutes, and it’s apparent he is a roll-up-your-sleeves, down to earth, hard-working kind of guy. Born and bred in Durham, North Carolina, he says he and his younger sister were very influenced by their parents, who grew up during the Great Depression. “They grew up with a very strong work ethic”, Nye says of his parents. “They both worked very hard and both expected us to work very hard.”

It’s not surprising that Nye is at his desk at 6:15 every morning. It’s not just out of habit, he says, it’s mostly because his construction crews are on the job at that time too.

“If we have an incident at one of our plants and our plants open early, I want them to know if they’re making rock or cement or ready mix early in the morning, I’m in my office as well,” he says, “Because we approach this together. We have the same values and work ethic and the same focus is important all the way through our organization.”

A big believer in mentoring, Nye passes along these core values to his mentees at Martin Marietta. His best leadership advice is something he learned from his law school professor. “Guard your reputation jealously,” he says emphatically, “because it’s something if you ever lose it, you will work for a lifetime trying to get it back.”

Watch the above video for more from our conversation with Nye.