Interim director of athletics Matt Tanney chose Fisher over fellow finalist Rob Ash, who was head coach at Montana State for nine seasons before being fired in November.
Fisher has more than 30 years of experience as a college coach and spent the last two seasons with Richmond, including as wide receivers coach and director of recruiting in 2014.
"I am honored and humbled to be named the head football coach at Western Illinois University," Fisher said in an official statement released by the university. "This team has a great foundation and a really good nucleus of talent returning. I'm excited to keep building this program as a contender in the Missouri Valley Football Conference, continue on the great tradition of winning football and being part of a great community."