Professional Headshot of Seth Miller Gabriel

Seth Miller Gabriel

Infrastructure & P3s Practice Leader

Executive Summary

Seth is the co-lead of the firm’s Infrastructure and Public-Private Partnerships (P3s) team based in Washington, DC. For more than 18 years Seth has been a leader in the public-private partnership, innovative project delivery and project governance structuring field. He has advised public owners, private sector partners or been the public owner in nearly every jurisdiction active in the P3 space in the United States. Seth has also advised countless foreign governments and organizations in the creation of P3 government units. 

He joined BDO from AIAI, the national P3 trade association in the United States where he serviced as Director of Programs and Initiatives. Prior to AIAI, Seth was appointed as the first Executive Director of the Office of Public-Private Partnerships for the District of Columbia. Prior to this appointment he was a P3 adviser and Director of Operations for the Institute for Public-Private Partnerships (IP3). Before joining the IP3 team, Seth was with the Jacobs’ National Transportation Consultancy team. As an independent consultant before Jacobs, he assisted national and international private sector firms with entering the Public-Private Partnerships market. Prior to undertaking independent consulting, he was the Deputy Executive Director of the National Council for Public-Private Partnerships (NCPPP), a nonprofit organization in the United States focused solely on increasing usage of the partnership model. Before serving the P3 community at the NCPPP, Seth was a member of Big Four’s Global Infrastructure and Project Group. 

Beyond serving as an advisor to private sector firms in every sector and governments at all levels, Seth has worked to professionalize the P3 field. He has co-authored works on the topic, has spoken at both domestic and international events, hosted countless foreign delegations with the State Department Visitation Program, and has taught a graduate level course on P3s.

  • Member, Association for the Improvement of American Infrastructure (AIAI)


  • M.P.A., George Washington University
  • B.A., Washington College