If tough assignments are a measure for the character of an individual, there are few people that can stand either next to or in the shadow of Michael Chertoff.

Known to much of America and the world for his nearly four years of service (2005-2009) as the second secretary for the U.S. Department of Homeland Security (DHS), Chertoff has been no stranger to tough jobs.

Whether it be serving as a federal judge on the U.S. Court of Appeals, the assistant attorney general for the Criminal Division at the U.S. Justice Department, a U.S. Senate counsel, or a federal prosecutor taking on Mafia kingpins or other criminals, Chertoff has never shied away from tough battles against formidable forces.

To those who have worked with him, he is known for his ability to get to the point and to get to it quickly. Drawing upon information before him and his own research, personal network, and instincts, Chertoff’s innate ability to focus onto the crux of an issue or problem has been described by many as “laser-like.”

Having turned the DHS secretary’s office over to his friend and former Justice Department colleague, Arizona Gov. Janet Napolitano, in late January 2009, he has set up his own firm, The Chertoff Group, in downtown Washington. Advising U.S. and international clients on a range of issues, the former secretary continues his busy pace of work, having just completed his first book, Homeland Security: Assessing the First Five Years. Chertoff sat down for an interview to reflect on his time as the leader of DHS and what the challenges ahead will be.

Rich Cooper: Mr. Secretary, looking back at your nearly four years of service at DHS, what are the accomplishments that you are most proud of and what were some of your greatest frustrations?

Michael Chertoff: Well, the bottom line, the accomplishment that was most significant is the fact that we did not have another successful attack against the United States. I think in many ways that’s the ultimate measure. At a somewhat less high altitude, I would say we dramatically changed and increased the security for people coming into the country. We transformed the way we deal with people at the ports of entry, not only bringing 10-print biometrics into effect, but also biographic collection and analysis based on commercial airline data.

We have more robust requirements for crossing our land border in terms of documentation, and even between the borders. You know we built 630 miles of fence, more than doubled the Border Patrol, and according to the reports I got from the Border Patrol just about a month ago, there’s been essentially a two-thirds reduction in the flow [of illegal immigrants] across the border. In some areas where we used to have thousands a day, there are now five or six a day.

Your job has been described by Sen. Joseph Lieberman (I-Conn.) and others as the toughest job in Washington. What do you know now after having been through that job that you wish you had known when you took the job back in March 2005?

I think I knew the breadth of the department. What you don’t appreciate until you get the job is the sheer variety of issues you’re going to deal with on a daily basis and, of course, every day you’re dealing with weather-related matters, terrorism-related matters, immigration matters, issues having to do with regulating the chemical industry, and all that can come up in a single day.

To those who have worked with him, he is known for his ability to get to the point and to get to it quickly. Drawing upon information before him and his own research, personal network, and instincts, Chertoff’s innate ability to focus onto the crux of an issue or problem has been described by many as “laser-like.”

That makes it a fascinating job, but I think in terms of understanding what your day’s going to be like, it gives you some sense of the sheer breadth of the subject matter you’re going to be covering.

I always go into a job by saying to myself: “Inevitably, your plans are going to be distracted and frustrated by events that occur, so what are the most important things you have to accomplish? Focus on those, and make sure you drive those to conclusion.”

Only one other person has had the job of DHS secretary before, but it’s one of those positions, as you alluded to, that you never know what’s going to happen day-in, day-out. What’s the best piece of advice someone gave you as you took the reins of DHS?

I think it was someone who said, “Make sure you keep getting plenty of exercise,” which sounds silly, but in a way, what they’re saying is, “You could spend all your time working. You need to be able to re-charge your batteries a little bit.” In my case I exercise. I go out running. And what it enables you to do is to keep some balance. You could be completely absorbed with work-related things 24/7.