The American scientist invented the computer language LISP.
It went on to become the programming language of choice for the AI community, and is still used today.
Professor McCarthy is also credited with coining the term “Artificial Intelligence” in 1955 when he detailed plans for the first Dartmouth conference. The brainstorming sessions helped focus early AI research. via BBC
October 25, 2011
This is a long and thoughtful piece from someone who worked with McCarthy.
http://www.abnormaldistribution.org/2011/11/11/john-mccarthy/