He received a bachelor's degree in mathematics and computer science from Santa Clara University. He then went on to earn his master's degree from the University of Illinois in 1985. Later on, Eich worked at Silicon Graphics for seven years and MicroUnity Systems for three years, which allowed him to develop his skills in writing code.
Eich is responsible for the development of JavaScript and was a co-founder of the Mozilla project. Eich created JavaScript in 1995 after being instructed to create a language similar to Java. Creating the first version of this language took Eich ten days to do, originally calling it "Mocha", but was renamed to "LiveScript" later that month. By the end of the year, Eich's creation was called JavaScript and was consistently being used in the Netscape Navigator Web browser. A few years later in 1998, Eich became one of the co-founders of the Mozilla project, which was used to manage programmers using the internet and the different layers of the browsing market.