Originally founded as the Twin Valley College in 1885, the school was reorganized as the all-boys Miami Military Institute in 1894.

In 1885, Orvon Graff Brown, a 22-year old professor at the Cincinnati Wesleyan University, leased a disused building in Germantown.

In December 1903 a fire destroyed the original Germantown Institute building, and a new campus was completed by the start of the 1904 school year.

Due to increasing maintenance costs, the former MMI Campus was sold in the 1990s and a new building was constructed nearby for Camp Miami, which continued to operate into 2001.

Most of the exterior windows had been broken by vandals and urban explorers trying to gain entry, and the roof was on the verge of collapsing due to lack of maintenance.