John A. Harr was a native of Salem, and graduated from Roanoke College in 1940 with a degree in physics. After military service with the U.S. Army Signal Corps during World War II, he taught briefly at VPI and then pursued graduate studies at Harvard University. He took the M.S. degree at Harvard in 1951, and the following year became assistant director of the Harvard Computation Lab, supervising the programming and operation of the Mark IV Computer.
Harr joined the Bell Telephone Laboratories in 1955, and since then he has designed central control equipment and programmed electronic switchgear. Harr supervised the design and programming of the first production model of an electronic switching system which was placed into commercial service for Bell Labs. He obtained many patents for his electronic inventions and wrote several articles for professional journals.
John A. Harr was awarded the Roanoke College Medal on April 2, 1971 for his distinctive service and professional achievement. He ended his career as head of the exploratory programs department, with responsibilities for exploring and planning future program controlled electronic switching systems. John and his wife, Mrs. John A. Harr raised three children together; Nancy H. Piretti, John A. Harr Jr., and Kathleen V. Breen.
John Harr received the Roanoke College Medal in 1971.