Ritchie joined Bell Labs in 1968, focusing his research on the design of computer languages and operating systems. After contributing to the MULTICS time-shared operating system in the 1960s, he and Bell Labs researcher Ken Thompson created UNIX in 1969® the operating system of most large Internet servers, businesses and universities. Later Ritchie designed and implemented the C Language for use on the UNIX operating system. Prized for its efficiency, C has since spread to many other operating systems and it is one of the most widely used programming languages.

Ritchie's current research at Bell Labs focuses on further refining the standards and technologies for the C software language. The goal of this research is to increase the reliability and security of this software to the point that it is not only ideal for all sorts of commercial applications but can be relied on to operate in long-term, unattended environments such as unmanned space exploration.

Ritchie holds an undergraduate degree in physics as well as masters and doctoral degrees in applied mathematics from Harvard University. He has been jointly awarded the ACM Turing Award, the IEEE Emmanuel Piore Award, the Richard W. Hamming Medal and the U.S. Medal of Technology.

Kenneth Thompson, retired Bell Labs Scientist, is one of the recipients of the 2003 Harold Pender Award, the highest honor bestowed by the University of Pennsylvania's School of Engineering and Applied Science. He shares this award with Mr. Ritchie.