MXR Innovations was founded in Rochester, New York in 1972 by Keith Barr and Terry Sherwood who were high school pals. The Phase 90 was the first effects pedal that was produced and remains in production today. Along with the Phase 90, the Blue Box and Distortion Plus followed and they went on to produce many effect products, including the Dynacomp.

In 1987, MXR was bought by the world famous Jim Dunlop company, who had developed a wide array of music products including capos, picks, and effects units as well. The Dunlop company still produces many of the original MXR products to this day.