He was professor of electrical engineering at Technical University of Budapest and the author of the popular tabletop book A Cultural History of Physics (A fizika kultúrtörténete, 1978).

He is the father of Charles Simonyi, a prominent computer-software executive who oversaw the creation of Microsoft Office.

[1] Simonyi was born the seventh of ten children in a small village in western Hungary.

Following World War II, he taught electrical engineering at the University of Sopron and in 1952 he became a professor at the Technical University, where he was known as an outstanding teacher and organized the Department of Theoretical Electrical Engineering.

[4] Károly's paternal grandfather was Sándor Simonyi-Semadam, who, as prime minister in the aftermath of World War I, signed the Treaty of Trianon.