Terrell Siegfried began his career with Hall Estill and practices primarily in the Corporate/Commercial, Tax and Estate Planning areas. He has been named an Oklahoma Rising Star in Business/Corporate Law by Oklahoma Super Lawyers. In addition, in April 2011 he was named to Oklahoma Magazine's 40 Under 40 list and in February 2012 he was named to Tulsa Business Journal's 40 Under list. Terrell was a 2012 recipient of the Leadership in Law award presented by the Journal Record.
- University of Notre Dame Law School (J.D., 2007)
- University of Tulsa (B.B.A. in Management, 2002)
- Oklahoma, 2007
- Board Member, the NORDAM Group, Inc.
- Board Member, University of Tulsa College of Law, Dean's Advisory Board
- Board Member, Tulsa Charity Flight Night, Inc.
- Board Member, St. Philip Neri Newman Center
- Board Member, Gilcrease Museum National Board
- Co-Chairman, Gilcrease Museum Collector's Reserve and Rendevous Committees
- Committee Member, Cascia Hall Preparatory School Special Committee
- Committee Member, University of Tulsa Scholarship Endowment Committee
- Gilcrease Museum, American Art Committee
- 2010, Cystic Fibrosis Foundation, Tulsa's Top 20 New Leaders
- 2008, Street School, Outsiders Party
- University of Tulsa Letterman's Association
- University of Tulsa President's Council
- 2007 - Present Hall Estill
- Oklahoma Bar Association
- Tulsa County Bar Association