One of the things that has helped my success is that I have switched careers many times.

I have worked in government and academia. I’ve started up a company and also worked in a strong, innovative company.

It all started during my undergraduate studies, when my “heart was touched by fire,” to quote Oliver Wendell Holmes.

My plan was to graduate and go to law school, but as I studied international relations, I realized how excited I was about the topic.

I discovered my passion: I wanted to support the security of the country. This was during the Cold War, when there was a lot of tension. I was worried about my country’s future, and I wanted to contribute to its success.

JD Crouch II is the chief executive of QinetiQ North America. (QinetiQ)

I decided not to go to law school.

In my graduate studies, I had written an op-ed piece about intermediate-range nuclear forces that was published in the Chicago Tribune.

That was a hot topic at the time. Someone in the U.S. Arms Control and Disarmament Agency saw it. They were interested in hiring someone in that area. They contacted my professor, and I got an interview.

So I began as a foreign affairs officer in that agency.

Eventually, I spent time in the executive branch in the Reagan administration helping to negotiate nuclear arms treaties.

I next went to work for a senator on the Armed Services Committee, where I worked on a very broad range of issues.

From there, I was principal deputy assistant secretary of defense in the George H. W. Bush administration. Then I decided to teach defense and strategic studies at Southwest Missouri State University. People thought I was crazy to leave, but I knew that in one’s career, it is important to make moves when they are right for you and your family.

Later, in the George W. Bush administration, I was assistant secretary of defense, ambassador to Romania and then deputy national security adviser in the White House.

One of the greatest achievements during my service under President George W. Bush was helping him think through the issues in Iraq that ultimately led to what became known as “the surge.” That increase in American troops in Iraq really helped to fundamentally change the situation there in a positive way.

The circumstances were very tough, both politically and on the ground. Trying to build confidence and trust was critical in getting a recommendation that could be implemented.

I saw the importance of hiring and attracting good people. You have to give them the authority, trust and confidence to succeed. I saw how you have to let the people on the ground execute, whether in business or government, and help them set the conditions for success.

When I left the administration, I did a soul search. What was important to me? I really liked leading teams, and I wanted to apply that in business.

So I founded an Internet start-up. It was successful, but it was a very difficult challenge to start with low capital and turn a good idea into a successful business.

Then I settled on QinetiQ North America. I was hired to do strategy and business development work. I built an effective team in one of the operating groups where we delivered a lot of innovative products.

This is a company that is focused on supporting the federal government and the war-fighter. That’s a really important quality to me.

— Interview with Vanessa Small

J.D. Crouch II

Position: Chief executive of QinetiQ North America, a subsidiary of QinetiQ Group. QinetiQ North America is a Reston company that delivers technology, services and solutions for global markets, focusing on U.S. government and commercial customers.

Career highlights: President, Technology Solutions Group, QNA; executive vice president, Strategic Development, QNA; assistant to the president and deputy national security adviser; U.S. ambassador to Romania; assistant secretary of defense, Defense Department.

Age: 54

Education: BA, MA, PhD, international relations, University of Southern California

Personal: Lives in McLean with his wife, Kristin, daughter, Lara, and son, Jake.