Rex has over 40 years of professional and business experience. He co-founded and operated a regional PEO for 12 years until its sale in 1995. He served as president of NAPEO in 1993-94 and has served in numerous other chapter and national leadership roles in the PEO industry over the past two decades, including chairing the national government affairs, standards and education committees.

Rex was instrumental in establishing the Arkansas Employee Leasing Act in 1992, the first state licensing law for PEOs in the nation, and in defining the concept of co-employment, which serves as the legal foundation for the PEO industry. In 2000, he received NAPEO's Michaeline A. Doyle award for outstanding service to the PEO industry.

Prior to entering the PEO industry, Rex had a successful 15-year career in water resources engineering, serving as a researcher and consultant for several national companies and government agencies. He holds MS and PhD degrees from Oklahoma State University.