After military, Pentagon career, PhD student starts fulfilling lifelong dream

Leslie Gillespie-Marthaler touring a site adjoining Sterling Ranch in Colorado. (Heidi Hall/Vanderbilt University)

Leslie Gillespie-Marthaler spent almost two decades as a U.S. Army officer, defense contractor and Pentagon and EPA employee, promoting sustainability across installations and federal agencies.

She helped break barriers in two areas dominated by men – the military and engineering – gaining authority and respect in both well before the age of 40. She left Washington, D.C., after advising more than 50 federal agencies on how to set goals to reduce greenhouse gases and report their progress.

Now Gillespie-Marthaler is earning a PhD in environmental engineering, fulfilling a dream she’s nurtured since the age of 9. She wants to examine the crossroads of sustainability and resiliency — the ability of environmentally friendly infrastructure to withstand extreme events.

Vanderbilt University School of Engineering’s partnership with Sterling Ranch, Colorado, a smart, sustainable city being built south of Denver, is opening doors for her research. Gillespie-Marthaler spoke about how her career path led to Vanderbilt and her potential work at Sterling Ranch.

When was the first time you knew you wanted to be an engineer?

I actually thought I wanted to be a marine biologist or an astronaut. And I was very into my causes. I’d joined Greenpeace and Amnesty International by the time I was 15.

I recognized early on that I wanted to do important work, but I knew I wouldn’t be able to attend an expensive university. I started looking at the service academies and applied to the Air Force Academy and West Point. When I realized I had bad eyesight and the Air Force would never let me near a fighter jet – they’d probably never even let me fuel one – I started really looking at West Point and got my nomination. Environmental engineering was the closest thing to what I started out wanting to do.

Historically, girls have faced not-so-subtle discouragement from pursuing the math and science fields. Did you?

I truly was better at arts and humanities and languages, but I realized math and science were important and never considered that I didn’t need to be proficient at them. I came from the public school system into a very challenging private school, and I had a math teacher telling me I had gaps in my mathematical background. I literally started teaching myself algebra. By the time I got to West Point, I was proficient in calculus and loved physics.

Now I’m doing graduate-level math and science again. At first I thought, “My math brain is broken.” Little by little, the wheels started cranking again. You’ve got these younger students who have gone straight through from undergrad to master’s to PhD, so I think it’s safe to say I’m one of the slowest people in these classes, but I just do it and get help and ask questions.

Did you get to use your environmental engineering bachelor’s in the military?

My work was in strength management reporting, and my last assignment was in Korea. There were about 27,000 people on the peninsula, and I had to look at all their skills and specialties vs. where the Eighth Army needed to be.

But I learned a lot about strategic planning and being detail oriented, and I interfaced with high-ranking individuals and was given leadership opportunities that a 20-something isn’t typically offered. I learned to manage people and work in a strategic mindset. Learning those things very early on significantly shaped who I am and how I look at things. You take responsibility for what goes wrong and what goes right, you’re only as good as the people working for you and with you, and you learn to say, “I screwed this up, and I’m going to fix this.”

Your career eventually took you to Washington, D.C. What did you do there?

I was an engineering consultant supporting first the Chief of Naval Operations on environmental programs and then the Assistant Chief of Staff of the Army. We started developing tools to assess how we rate and project the quality of resources for Army installations – air, water, land, transportation, radio frequencies – and how we best manage shared resources, zoning issues, real estate issues. Any factors that could constrain an installation’s mission, we wanted to determine what those were.

After contracting, I held a series of positions with the Army and ended up responsible for managing all environmental policy and programs, including sustainability and climate change. When the first Obama administration required all federal agencies to develop and publish 25-year strategic development plans — plus set up a system for greenhouse gas reporting and set goals for the entire federal community — I jumped at the opportunity to be a part of the effort. I worked with White House staff and federal leaders to train 50 plus agencies to get ready to do this.

You were trying to get your PhD at George Washington University while doing all that. Were you tempted to give up that dream?

Yes. My mom was ill, so I came to Nashville to help her recover and was working in consulting and had my son. When things started getting stable, I decided it was time to look at what I was going to do next: Finish that PhD, or go back to full-time work. Part of me felt, if I can make a lot of money, shouldn’t I to ensure my son’s future? But there was another part that said, isn’t reaching a goal of a PhD also valuable to my son?

I applied to one school – Vanderbilt — and a ton of jobs in the federal government. I got accepted to Vanderbilt for the fall 2015 semester. My husband was happy, my family was happy and my son is getting to go to an incredible child development center here.

Construction begins on Sterling Ranch.

How is our partnership with Sterling Ranch helping with your research goals?

There are so many ratings and certifications to tell you how sustainable and energy efficient that homes and other buildings are – LEED, HERS, EnergyStar, WaterSense, Living Building Challenge – but if you have the ability to do smart metering, to capture and analyze data about water and energy, you can gather quantifiable data on how they’re really performing. You can make better decisions at the home and community level about how to use resources.

I haven’t defended a proposal yet, but I’m starting a comparative analysis of the subjective measures that are available. If there’s no perfect tool, what are the components of each of those, and how can we make them work together?

I’m also interested in where sustainability and resilience intercept. As a nation, we went from being environmentally conscious to minimizing impact to thinking about sustainability. Now we’re looking resilience. For instance, water infrastructure on the national scale — it has to respond to things it wasn’t designed for, like rapid variation in floods, drought and severe weather. With Sterling Ranch’s 20-year build-out, we’ll be able to look at events like those over time.

Now that you’ve been here for a semester, what do you think of your choice to pursue a PhD?

Universally speaking, every single person I have encountered has made me feel I am in the right place. This is the me that solves problems and sees possibilities, and Vanderbilt gave that back to me. I don’t wonder about who’s smarter than me, I know who I am and what I can do. I can literally feel my intellectual capacity expanding.

People might be afraid of a PhD, of stopping mid-career to do something because they think they’re in too deep and it’s too risky and too hard with kids and a family. You just have to be true to yourself. If it’s your life goal, don’t regret it down the road.

If I can make my brain do advanced math and science after all this time, I feel any qualified person can come in and do this.

Leslie Gillespie-Marthaler’s Bio


  • George Washington University, professional degree, engineer, 2011
  • Georgia Institute of Technology, master’s in civil engineering, 2002
  • United States Military Academy, bachelor’s in environmental engineering, 1994


  • Ph.D. Student, Vanderbilt University, Environmental Engineering, 2015-present
  • U.S. Environmental Protection Agency, Office of Research and Development, assistant center director and senior adviser to assistant administrator, 2011-12
  • U.S. Army, Office of the Assistant Secretary of the Army for Installations, Energy, and Environment, director of army sustainability policy and environmental programs, 2008-11
  • U.S. Army, Office of the Assistant Chief of Staff of the Army for Installation Management, senior program manager/budget officer, 2006-08
  • Booz Allen Hamilton, associate, 2004-06
  • SAIC, senior environmental engineer, 2003-04
  • U.S. Department of Agriculture, Forest Service, program manager, 2003
  • Georgia Institute of Technology, graduate student, 2001-02
  • SAIC, Fort Bragg, N.C., sustainability master planner, 1999-2001
  • U.S. Army active duty, Adjutant’s General Corps, 1994-99


Heidi Hall, (615) 322-6614
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