The original institution at this location was Rock River Seminary, which was founded by the Methodist Church in 1839.
The Brethren reorganized the school and reopened it in 1879 as Mount Morris Seminary and Collegiate Institute.
However, by the end of World War I, enrollments began to decline, and financial problems continued to plague the college.
Enrollments began to rise again in 1929–1930, but another fire in April 1932 destroyed a dormitory and heavily damaged some classroom and administrative buildings.
Mount Morris College was a member of the Illinois Intercollegiate Athletic Conference from 1922 to 1931. Notable alumni of Mount Morris College include: Notable alumni from the Methodist Rock River Seminary include: