Our People

At Halff, we’ve built one of the nation’s largest engineering and architectural consulting firms on a core tenet: Focus on people, treat them well, and success will follow. So we hire the industry’s most talented professionals, make them owners and continually develop and reward them. After all, Dr. Halff believed that a company is nothing more than the sum total of its people.

Employee Spotlight

Take a look at the people who make our firm great.

Ashley Purkey

Public Works Team Leader

“I come to work every day with the goal to ‘improve.’ This is applied in different situations daily, but I always want to make something that I work on better. Some days the priority is to improve a project by devoting time and energy into developing the best possible design, others I want to improve how my coworkers interact. There are some days where I simply want to improve someone’s day by talking to them beyond the daily work conversations. I want to improve lives every single day in whatever form it may take.”

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Vasileios Kalogirou

Survey Practice Leader

“Halff values growing and developing people that stems from the leadership team through any entry level position.”

Sofia Carrillo

Graduate Civil Engineer

“It is important to me that I’m working for a good company who supports its employees. I began working for Halff a couple of months before the pandemic hit (fresh out of college). As a young engineer, Halff supported me as I became an officer in the American Society of Civil Engineers (ASCE) and allowed me to grow in my passion and career at conferences across the country.”

RJ Endsley

Operations Manager

“When you walk into the door at Halff, you’re surrounded by an entire company of people who are not here to punch the clock but are here working on projects in their community, doing their best to move those communities forward.”

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Melanie Cleavelin

Public Works/Transportation Team Leader

“We have enough resources that we will always have an expert to help our clients out. We are responsive to their needs and take full responsibility for our work.”

Russell Killen

Operations Team Leader

“I enjoy working at Halff because of the collaborative teamwork approach and relative absence of unhealthy competition and drama. Our culture is a family atmosphere that thrives in an environment of quality, creativity and accountability.”

Sherri French

PLA Deputy Practice Leader

“My career at Halff means so much to me. I am developing meaningful relationships, expanding my technical knowledge and leadership abilities in such a way that I am a better person outside of work because of what I am doing within Halff. I’m so grateful I’ve found a company I can grow with over time.”

Gabriel Benavides

Electrical/ITS Team Leader, MEP Practice QA Manager

“When the client is happy, we are happy. I love providing clients with excellent quality of service to gain their confidence, friendship and business.”

Edjuan Bailey

Land Development Deputy Practice Leader

“One of the most satisfying things about working at Halff is the exposure to an incredible diversity of thought, both with employees and clients. This type of collaboration allows us to develop more innovative solutions and to improves lives and communities. At Halff, it really is all about the people.”

Mark Llewellyn, Jr.

Operations Manager

“We are a large full-service professional consulting firm with a small company approach to supporting our people and our clients. We strive to be trusted advisors through establishing strong relationships built on trust and confidence.”

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Leadership Team

Creating a culture built on people requires the right people at the top.


Mark Edwards, PG

“I’m truly inspired by the exceptional people of Halff and driven to expand our reach through growth, as growth creates opportunities for our people. We provide our people autonomy and flexibility to achieve their goals while working collaboratively to provide a responsive quality service to our clients.”

“I’m truly inspired by the exceptional people of Halff and driven to expand our reach through growth, as growth creates opportunities for our people. We provide our people autonomy and flexibility to achieve their goals while working collaboratively to provide a responsive quality service to our clients.”

Mark began his career as a petroleum geologist in 1984 and joined Halff in 1990. He started with the Environmental practice and initiated the Oil and Gas Services practice in 2006. He served on the board of directors from 2013 to 2015, joined the leadership team and became executive vice president in 2015, and now serves as president/CEO. He is passionate about creating a culture that ensures all employees reach their full potential.

Mark lives in Plano with his wife, Desiree. Their favorite pastime is spending time with their three adult children. Otherwise, you may find Mark painting or “recharging” at the lake.

Chief Operating Officer
Todd Jackson, PE
“During my career here, one thing has remained unchanged: Halff has great people, great projects and great career opportunities.”

As chief operating officer, Todd leads the operations team and managing firmwide processes. Engineering has always been in his blood; his father and brother work as engineers and his mother as a math teacher. He joined Halff’s Public Works practice after graduating from Louisiana Tech University in 1996. He helped open the company’s Austin office in 2002 and began overseeing the Austin, San Antonio, Houston, Conroe and Tyler offices. He was named executive vice president in 2018. He serves on the HCI board of directors, is a member of ACEC’s Austin Chapter, and served on the company’s board of directors from 2016 to 2019.

In his community, Todd serves on the Georgetown Chamber of Commerce and Williamson County ESD No. 4 boards. He has also been an elder at his church in Georgetown and has coached more than 40 basketball and baseball teams for his three children, Tyler, Reed and Kate. In his free time, there’s a good chance you’ll find him hunting, kayaking or singing and playing music with his kids.
Chief Strategy Officer
Russell Zapalac, PE
“In the words of Johnny Cash, I’ve been everywhere, man.”

Russell joined Halff’s leadership team as chief strategy officer and executive vice president in 2016. Prior to coming to Halff, his career has taken him from Miami to Anchorage and almost everywhere in between, on a multitude of civil engineering projects, primarily large transportation facilities. He’s worn many hats—contractor, consultant and owner—and is known nationally as an expert in public-private partnership projects.

Russell earned his BS in Civil Engineering from the University of Texas at Austin. He is a former board member of the American Road and Transportation Builders Association and was the organization’s 2014 Public Sector Entrepreneur of the Year. He “grew up on the water” and is an avid outdoorsman. When he’s not working, you’ll likely find him spending time on Lake Travis in Austin or in Colorado with his wife, Kim, and his son’s family.
Chief People Officer
Jessica Baker Daily, PE, CFM, PMP
“I love nothing more than seeing people in our firm grow in their abilities and confidence in taking on new roles and challenges.”

Jessica has lived by a “work hard, play hard” mentality since she began her career at Halff as an intern in 2003. She joined the firm’s Water Resources practice after graduating from The University of Texas at Austin, and quickly became a team leader. She was named vice president in 2015, and assumed leadership of the Marketing team when she became an executive vice president in 2019. Jessica joined Halff’s Leadership Team as chief marketing officer in 2021, continuing to grow our marketing and communications efforts and position the firm as a leader in the competitive A/E industry.

She now serves as Halff’s chief people officer, a role that will allow her to help create an authentic employee experience for everyone at Halff. She will influence areas such as employee satisfaction, workforce engagement, benefits and compensation, training opportunities, employee belonging and communications as she strengthens connections across the firm.

Jessica serves on The University of Texas Civil, Architectural and Environmental Engineering School’s External Advisory Committee (EAC). She is a director on the board of the American Council of Engineering Companies (ACEC) Dallas and is a graduate of the Dallas Regional Chamber’s Leadership Dallas program. She was named to Engineering News-Record’s national Top 20 Under 40 list in 2018, received the Outstanding Young Alumna Award at The University of Texas at Austin’s Cockrell School of Engineering in 2014 and received the Roy D. Sedwick Service Award from the Texas Floodplain Management Association.

Jessica and her husband Brett have a son, Bennett, and live in the Lake Highlands area of Dallas. Their favorite activity is travelling and exploring new destinations.
Chief Financial Officer
Joseph Sagel, PE
Joseph’s career at Halff began with a newspaper ad fresh out of college in 2005. He became an engineer in the company’s Land Development and Public Works practices, working at three offices over nine years. He joined the Accounting department in 2014 as financial manager before advancing to finance director. As an engineer working in accounting, Joseph “bridged the gap” between the Accounting and production teams throughout the company. He began serving Halff as chief financial officer in 2020.

Joseph graduated from Trinity University in 2005 and earned his MBA from Southern Methodist University in 2009. When he’s not working, he enjoys spending time with his wife, Cassie, and cheering on his three children, Mirabelle, Lillian and Grayson, at soccer games and gymnastics meets during the weekends.

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