[2] He was a house officer in internal medicine at the Graduate Hospital of the University of Pennsylvania from January 1958 to June 1960.

Upon competition of his Military Service Gillenwater completed his residency in urology at the Hospital of the University of Pennsylvania in 1965.

During his tenure as chairman, Gillenwater made headline news when he introduced the lithotripter for the treatment of kidney stones without surgery in America.

[4] Gillenwater with the support of Hovey Dabney, was responsible for the creation of University of Virginia Health Sciences Foundation, with a significant institutional impact enabling innovation and discovery for clinical practitioners and scientists.

Gillenwater married Shirley Brockman, also from Kingsport, in 1955, and they have three children Linda, Ann and Jay Merritt.