Clay began his career in the mid-1970s creating and representing special purpose districts in the greater Houston area.

He was appointed to the City of Houston Housing Improvement Program Review Committee and later to the Houston Parks Board. He also served as General Counsel to the Association of Water Board Directors and a board member of the Utility District Advisory Counsel.

In the early 1990s, Clay moved to Dallas and served as special counsel to entities affiliated with the Trammell Crow organization responsible for the formation of a public/private partnership that financed construction of Lone Star Park at Grand Prairie, as well as operation and disposition of a portfolio of retail sewer companies. For the past 23 years, he has served as general counsel to various types of special districts located in the Dallas-Fort Worth metroplex, as well as representing landowners and developers before local and state government in the creation of districts.