Our People

At Halff, we’ve built one of the nation’s largest full-service engineering 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.”

Vas Kalogirou portrait image

Vasileios Kalogirou

Survey Practice Leader

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

McKayla Benner Halff portrait

McKayla Benner

Graduate Civil Engineer

“At Halff, I have been able to pursue my interests by supporting two teams simultaneously. Both teams embody the contagious Halff culture. The environment I have experienced is one of empowerment, comradery, compassion and integrity. It extends to the client, and the relationships and communities flourish. Work can be found anywhere, but the culture at Halff is one of a kind.”

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.”

Melanie Cleavelin portrait image

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 Halff portrait

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.”

Vas Kalogirou portrait image
McKayla Benner Halff portrait
Melanie Cleavelin portrait image
Sherri French Halff portrait

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.
Steven Miller, PE CSO Halff portrait
Chief Strategy Officer
Steven Miller, PE
Steven Miller, PE CSO Halff portrait
“With strategic growth, we can continue taking care of our clients and communities while providing opportunities for our people.”

Steve brings a unique perspective and insight to everything he does. As chief strategy officer, he leads all strategic initiatives for Halff, integrating our Solutions, Marketing and Client Advocacy teams to deliver cross-collaboration across practices and geography, partner more effectively with clients and enhance growth opportunities for Halff’s employees. He joined Halff as senior vice president and Transportation practice leader before ascending to Mobility solutions leader in 2022. Additionally, he served on Halff’s Board of Directors for four years.

Steve obtained his bachelor’s degree in civil engineering from Oklahoma State University and earned a master’s degree in construction engineering and project management from the University of Texas at Austin. He is a member of the Muscogee (Creek) Nation and is active in Institute of Transportation Engineers (ITE), American Council of Engineering Companies (ACEC) and National Society of Professional Engineers (NSPE).

He lives in Austin with his wife, Jennifer, and their daughter, Danielle, where they are all active in autism and disability advocacy. When not working, you’ll probably find them traveling, hiking, kayaking or working in the garden, or find Steve minding the smoker on the back porch.
Portrait of Halff's Chief People Officer (CPO) Jessica Baker-Daily
Chief People Officer
Jessica Baker Daily, PE, CFM, PMP
Portrait of Halff's Chief People Officer (CPO) Jessica Baker-Daily
“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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