At the age of 17, Simonyi left Hungary on a short-term visa but did not return. He was hired by Denmark’s A/S Regnecentralen in 1966 where he worked with Per Brinch Hansen and Peter Kraft on the RC 4000 minicomputer’s Real-time Control System, and with Peter Naur on the GIER ALGOL compiler. He subsequently moved from Denmark 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 under Butler Lampson. He has honorary doctorate degrees from the Juilliard School in New York and from the University of Pecs in Hungary.

Simonyi was recruited to Xerox PARC by Butler Lampson during its most productive period, working alongside luminaries such as Alan Kay, Butler Lampson, and Robert Metcalfe on the development of the Xerox Alto, one of the first personal computers. He and Lampson developed Bravo, the first WYSIWYG document preparation program, which became operational in 1974. During this time he received his Ph.D. in computer science from Stanford University in 1977 with a dissertation on a software project management technique he called meta-programming. This approach sought to defeat Brooks’ law by scaling programming through a formalization of communication among programmers. In the 1992 book Accidental Empires ( ISBN 0-88730-855-4), Robert X. Cringely gave this description:

Simonyi became the second Hungarian astronaut and the fifth space tourist , the only one in history, who went twice to space as a space tourist who paid his own way on spaceflights. Earlier, the Hungarians were the seventh nation to be represented in the space, in 1980, by Bertalan Farkas’s spaceflight, 27 years before Simonyi’s first one, in 2007. The next Hungarian astronaut will follow Simonyi to the International Space Station by 2025.

In 1981, at Metcalfe’s suggestion, he visited Bill Gates at Microsoft who suggested Simonyi start an applications group at Microsoft with the first application being a WYSIWYG word processor. At Microsoft, Simonyi built the organization and applications of what became its most profitable products, Word and Excel, as well as Excel’s predecessor Multiplan. For the applications, Simonyi pursued a strategy called the “revenue bomb”, whereby the product ran on a virtual machine that was ported to each platform. The resulting applications were highly portable, although Microsoft’s focus and IBM’s standardization on MS-DOS eventually made portability less important. In a 2002 news item, The Age noted that Simonyi introduced the concept of metaprogramming at Microsoft, turning it into what people sometimes referred to as a software factory, but the metaprogramming concept “did not work out in practice.”

Since 1997 Simonyi has been a member of the National Academy of Engineering and became a member of the American Academy of Arts and Sciences in 2008. Since 1998 Simonyi has served as member of the Board of Trustees of the Institute for Advanced Study in Princeton and was its Chairman in 2008.

Simonyi remained at Microsoft during its rapid rise in the software industry, becoming one of its highest-ranking developers. He left Microsoft in 2002 to co-found, with business partner Gregor Kiczales, a company called Intentional Software. This company markets the intentional programming concepts Simonyi developed at Microsoft Research. In this approach to software, a programmer first builds a language environment specific to a given problem domain (such as life insurance). Domain experts, aided by the programmer, then describe the program’s intended behavior in a What You See Is What You Get (WYSIWYG)-like manner. An automated system uses the program description and the language to generate the final program. Successive changes are only done at the WYSIWYG level.

In 2003 he founded the Charles and Lisa Simonyi Fund for Arts and Sciences, a nonprofit organization based in Seattle. The foundation provides grants to outstanding organization in art, sciences and education. Grant recipients have included the Seattle Symphony ($10 million), and the Seattle Public Library ($3 million), the Metropolitan Opera, the Juilliard School and the Vera C. Rubin Observatory, which will host the Simonyi Survey Telescope. The $100 million foundation closed in 2013.

In 2004, Simonyi received the Wharton Infosys Business Transformation Award for the industry-wide impact of his innovative work in information technology.

In January 2004, Simonyi created the Charles Simonyi Fund for Arts and Sciences, through which Simonyi supports Seattle-area arts, science, and educational programs. As of May 2012, the Fund size was $75 million.

Simonyi was born in Budapest, Hungary. His father, Károly Simonyi, was a Kossuth Prize-winning professor of electrical engineering at the Technical University of Budapest, and created the first Hungarian nuclear particle accelerator. While in secondary school he worked part-time as a night watchman at a computer laboratory in the early 1960s, 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. In 2006 he said when he was young his dream was, “to get out of Hungary, go to the West and be free.”

In early 2006, Simonyi expressed interest in becoming a space tourist and signed agreements with the space tourism company, Space Adventures, Ltd., for a ten-day mission to the International Space Station (ISS).

In August 2006, he passed a pre-qualification medical exam by the Russian Federal Space Agency, called the State Medical Commission (GMK). He started training at Star City in September 2006.

He launched on April 7, 2007 (GMT), on board Soyuz TMA-10. He shared a ride with two Russian cosmonauts to the International Space Station, and returned aboard Soyuz TMA-9, landing on April 21, 2007.

Upon arrival to the ISS on April 9, 2007, Simonyi said, “It is amazing how it appears from the blackness of the sky. It was very, very dramatic. It was like a big stage set, a fantastic production of some incredible opera or modern play. That’s what I was referring to when I said I was blown away.”

Simonyi’s expected return on April 20, 2007, was delayed by one day due to ‘boggy ground’. He returned to Earth on April 21, 2007 along with an American astronaut and a Russian cosmonaut.

Charles Simonyi is a licensed amateur radio operator with the call sign KE7KDP, and planned to contact a number of schools while on his flight on the International Space Station using amateur radio for the communication with those schools. On April 11, 2007 the American Radio Relay League reported that Simonyi was already making ham radio contacts from space.

Simonyi is married to Lisa Persdotter, the daughter of a Swedish millionaire. She is 32 years his junior. They were engaged on 8 August 2008 and were married on 22 November 2008 in a private ceremony in Gothenburg, Sweden, attended by their closest friends, among them Bill Gates. Simonyi gained United States citizenship in 1982. Simonyi dated Martha Stewart for 15 years until 2008.

In October 2008, he booked for a second trip to the ISS through Space Adventures on board Soyuz TMA-14. On March 26, 2009 he returned to space aboard Soyuz TMA-14. He returned to Earth on board Soyuz TMA-13. Along with Soyuz Commander Yuri Lonchakov and Michael Fincke, Simonyi landed in Kazakhstan on April 8, 2009.

One of the schools Simonyi contacted was Cedar Point Elementary in Bristow, Virginia. A telebridge conversation was held on Tuesday, April 17, 2007. On board with him were Oleg Kotov and Fyodor Yurchikhin. On March 30, 2009 he held a phone conversation with students at the Girls’ Middle School in Mountain View, California, United States in which he said that one of the most surprising things about traveling to space was that upon returning to earth the air feels very thick, very heavy, like “breathing Pepto-Bismol.” He also stated that talking with the students from the school “made his day.”

On April 18, 2017, Intentional Software was acquired by Microsoft.

In February 2017, Simonyi and his wife Lisa gave the University of Washington Computer Science and Engineering (CSE) department $5 million towards the completion of a new building.