Mr. Close was the former Chairman of the Board of Expansion Seal Technologies Group, and former Chairman of the Board of CDS Analytical. Earlier in his career he was President of Continental Disc Corporation, Technical Investor at Kellet Corp, President and Chairman of Compudyne Corporation, and Founder and President of Fluid Controls Company. Over the years, he also published a number of technical articles on instrument controls and systems. Mr. Close was a Director at J.W. Microelectronics, Athena Controls, Kellet Corp., Chemical Data Systems, Instrument Society of America, and General Components. In addition, he was a trustee for the privately-held CDC Fund. 

In addition to the Drexel 100, Mr. Close was also inducted into the Alumni Circle of Distinction for the College of Engineering. As a student, he was President of the Chess Club and a member of the American Institute of Electrical Engineers.

He and his late wife, Barbara, established a philanthropic legacy that included a sizable anonymous gift in 1999 to Drexel University that helped launch and build the Baiada Institute for Entrepreneurship.

In March 2009, the Charles and Barbara Close Foundation gave Drexel $1.5 million to establish the A.J. Drexel Autism Institute, and in December 2012, the foundation’s gift of $12.5 million established the Charles D. Close School of Entrepreneurship.
 
Mr. Close, whom friends knew as “Charley,” enjoyed skiing, music, science, and was an avid golfer and member of the Cedarbrook Country Club in Blue Bell, PA. Charles D. Close passed away on September 6, 2009, at the age of 94. His legacy lives on in the generations of future entrepreneurs being educated in the Charles D. Close School of Entrepreneurship.