Charles Simonyi (Hungarian: Simonyi Károly; born September 10, 1948) is a Hungarian-American computer software executive who, as head of Microsoft's application software group, oversaw the creation of Microsoft's flagship office applications. He now heads his own company, Intentional Software, with the aim of developing and marketing his concept of intentional programming. In April 2007, aboard Soyuz TMA-10, he became the fifth space tourist and the second Hungarian in space. In March 2009, aboard Soyuz TMA-14, he made a second trip to the International Space Station. His estimated net worth is US$1 billion.
Simonyi was born in Budapest, Hungary, the son of Károly Simonyi, a professor of electrical engineering at Technical University of Budapest. While in high school he worked part-time as a night watchman at a computer laboratory, overseeing a large Soviet Ural II mainframe. He took an interest in computing and learned to program from one of the laboratory's engineers. By the time he left school, he had learned to develop compilers and sold one of these to a government department. He presented a demonstration of his compiler to the members of a Danish computer trade delegation.
He was hired by Denmark's A/S Regnecentralen in 1966 and moved to the United States in 1968 to attend the University of California, Berkeley, where he earned his B.S. in Engineering Mathematics & Statistics in 1972.