Kimley-Horn Executive and Leadership Team

August, 2026

Leadership Overview

Kimley-Horn has 9 executives leading key functions including finance, technology, operations, information systems, human resources, and regional leadership.

Driven by a commitment to excellence, Kimley-Horn provides comprehensive planning and design consulting across numerous disciplines, shaping infrastructure and communities nationwide.

Leadership Roles at Kimley-Horn

  • Chief Financial Officer - Tammy Flanagan
  • Chief Operating Officer - Aaron Nathan
  • President, Branch (Mckinney) - Joseph Riccardi
  • President - Catherine Hyland
  • President-Elect - Jonathan Oliver
  • President - Gary Garlow
  • Chief Technology Officer - J. Otto
  • Chief Information Officer - Jeff Witt
  • Senior Vice President, Director of Human Resources (Chief Human Resources Officer) - Lori Vannewkirk
  • Tammy Flanagan - Chief Financial Officer

    Tammy Flanagan, the Chief Financial Officer at Kimley-Horn, directs all financial operations and strategic fiscal planning. Overseeing budgeting, forecasting, and financial reporting, Flanagan ensures the firm's fiscal health and sustainable growth. This leadership role involves managing investment strategies and optimizing resource allocation across all service lines, including transportation, technology, and land development. By maintaining robust financial controls, Tammy Flanagan directly supports the company's ability to undertake large-scale projects and expand its market presence. Flanagan's expertise is critical in navigating complex economic landscapes and securing the financial stability necessary for Kimley-Horn's continued success and innovation in the consulting sector.
    Tammy Flanagan

    Aaron Nathan - Chief Operating Officer

    Aaron Nathan, the Chief Operating Officer at Kimley-Horn, directs the firm's day-to-day operational activities and strategic execution. Nathan oversees the efficient delivery of services across all disciplines, including roadway and bridge design, planning, and asset management. This critical role involves optimizing workflows, enhancing project management methodologies, and ensuring seamless collaboration between departments. By focusing on operational excellence, Aaron Nathan drives improvements in productivity and resource utilization, directly impacting project timelines and client satisfaction. Nathan's leadership ensures that Kimley-Horn consistently meets its commitments and upholds its reputation for high-quality consulting services nationwide.

    Joseph Riccardi - President, Branch (Mckinney)

    Joseph Riccardi, the President, Branch (Mckinney) at Kimley-Horn, directs regional operations and business development for the McKinney branch. Riccardi oversees the strategic growth and client engagement within this specific geographic market, ensuring alignment with the firm's broader objectives in areas like transportation, planning, and land development. This executive role involves managing local teams, fostering client relationships, and driving project execution to meet regional demands. By focusing on localized market needs and opportunities, Joseph Riccardi ensures the McKinney branch effectively serves its clients and contributes significantly to Kimley-Horn's overall success. Riccardi's leadership is key to expanding the firm's presence and impact in the region.
    Joseph Riccardi

    Catherine Hyland - President

    Catherine Hyland, the President at Kimley-Horn, provides executive leadership and strategic direction for the firm. Hyland oversees the company's overall performance, guiding initiatives across all service disciplines, including roadway and bridge, environmental, and aviation. This critical role involves setting the corporate vision, fostering a culture of innovation, and ensuring the successful execution of business strategies. By championing the firm's core values and client-centric approach, Catherine Hyland drives sustainable growth and enhances Kimley-Horn's market position. Hyland's leadership is instrumental in navigating the complexities of the consulting industry and maintaining the company's reputation for excellence.

    Jonathan Oliver - President-Elect

    Jonathan Oliver, the President-Elect at Kimley-Horn, prepares to assume executive leadership and contribute to the firm's strategic direction. Oliver supports current leadership in overseeing company-wide operations and initiatives, focusing on areas such as technology, integrated water, and asset management. This role involves gaining comprehensive insight into the firm's strategic planning processes and operational frameworks. By actively engaging with various departments and projects, Jonathan Oliver ensures a smooth transition and continuity of leadership. Oliver's dedication to understanding the intricacies of Kimley-Horn's business is crucial for future success and sustained growth in the planning and design consulting sector.
    Jonathan Oliver

    Gary Garlow - President

    Gary Garlow, the President at Kimley-Horn, provides executive leadership and strategic oversight for the firm's extensive operations. Garlow guides the company's vision and direction across all service lines, including transportation, transit, and land development, ensuring consistent delivery of high-quality consulting services. This leadership function involves fostering strong client relationships and driving business development initiatives nationwide. By focusing on operational excellence and strategic growth, Gary Garlow enhances Kimley-Horn's market leadership and reputation. Garlow's commitment to innovation and client success is fundamental to the firm's ongoing achievements and its impact on infrastructure and community development.

    J. Otto - Chief Technology Officer

    J. Otto, the Chief Technology Officer at Kimley-Horn, architects the firm's technological vision and implementation strategies. Otto oversees the integration of advanced technologies across all service areas, from transportation and transit to integrated water and environmental solutions. This executive function involves driving innovation in digital tools, data analytics, and software development to enhance project delivery and client value. By championing cutting-edge technological advancements, J. Otto ensures Kimley-Horn remains at the forefront of the industry, leveraging technology to solve complex design and planning challenges. Otto's leadership is pivotal in maintaining operational efficiency and fostering a culture of technological excellence throughout the organization.
    J. Otto

    Jeff Witt - Chief Information Officer

    Jeff Witt, the Chief Information Officer at Kimley-Horn, leads the strategic development and management of the company's information systems and technology infrastructure. Witt oversees the implementation of robust IT solutions that support all business operations, from planning services and land development to environmental and energy consulting. This executive responsibility includes ensuring data security, system reliability, and the effective deployment of digital tools for internal teams and clients. By driving technological advancements in information management, Jeff Witt enhances operational efficiency and supports data-driven decision-making across the firm. Witt's focus on information systems is crucial for maintaining Kimley-Horn's competitive edge and facilitating seamless project execution.
    Jeff Witt

    Lori Vannewkirk - Senior Vice President, Director of Human Resources (Chief Human Resources Officer)

    Lori Vannewkirk, the Senior Vice President, Director of Human Resources (Chief Human Resources Officer) at Kimley-Horn, shapes the company's talent strategy and organizational development. Vannewkirk oversees all human resources functions, including recruitment, employee relations, compensation, and benefits, ensuring a supportive and high-performing work environment. This leadership position is vital for attracting and retaining top talent across diverse fields such as transportation, technology, and landscape architecture. By fostering a strong corporate culture and implementing effective HR policies, Lori Vannewkirk directly contributes to employee engagement and the overall success of Kimley-Horn. Vannewkirk's strategic approach to human capital management is essential for the firm's continued growth and operational excellence.

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    Frequently Asked Questions Regarding Kimley-Horn Top Executives and Leadership Team

    Who leads Kimley-Horn?
    Kimley-Horn is led by Tammy Flanagan (Chief Financial Officer), along with executives such as Aaron Nathan (Chief Operating Officer) and Joseph Riccardi (President, Branch (Mckinney)).
    Who is part of Kimley-Horn’s executive team?
    The executive team of Kimley-Horn includes leaders such as Tammy Flanagan (Chief Financial Officer), Aaron Nathan (Chief Operating Officer), Joseph Riccardi (President, Branch (Mckinney)) and other senior executives.
    How many executives does Kimley-Horn have?
    Kimley-Horn has 9 executives leading key business areas.
    What roles are included in Kimley-Horn’s leadership team?
    The leadership team of Kimley-Horn includes roles such as Chief Financial Officer, Chief Operating Officer, President, Branch (Mckinney), President, President-Elect.